I borrowed the idea from TheSource in this thread, but thought it deserved a better name.

http://www.vgchartz.com/forum/thread.php?id=2878

So, I love a thread like this and TheSource, you're good at this stuff.

 I have a suggestion though, that we play around with millions of units and not just percentages (%).

First a quick look at last gen. My numbers aren't exact, but roughly:

Year     PS2                    Xbox                GC                 total market/cumul.

2000  20 mill                                                                20 mill /20m

2001  21m /41m           6.5 m                 7 m                34.5m /54.5m

2002  21m /62m           5.5m /12m         4m /11m        30.5m /85 m 

2003  22m /74m           6m    /18m         5m /16m        33m    /108m

2004  21m /95m           5m    /23m         4m /20m        30m    /138m    

2005  15m /110m         1m    /24m          -   /20m         16m    /154m

Note: 2001 actually means total sales from oct '00 - oct '01 and so forth, I put it this way to better illustrate the one year head start (world wide market) that the PS2 got over the other 2 consoles.

 So for comparisons sake, let's assume the length of this gen is 5 years + the 1 year head start of X360, which would give us a life-span of oct 2005 to dec 2011. So let's skip 2012 (and BTW, many believe there is at least a new Xbox and Nintendo by then).

You see from my table that the totals for last gen is 154 million, since I don't want to count the PS2 sales that came after the PS3 was released. This gives us roughly totals of 110m for PS2, and as we all know 24m XBOX and 20m for GC.

 Also, you can see that for the most part of last gen, the total sales were on average 32 million consoles/year, from which PS2 took about 21 mill/yyear leaving 11 million for Xbox and GC to split.

Now, I'm not ready to predict the totals for this gen yet, but I want to argue about it and also see others here make excellent predictions. So I'd like to put forward a few factors to be aware of when predicting the current gen:

- TheSource had total market sales accumulated through 2011 at 170 mill consoles. That suggests a yearly figure of 32mill units just like last gen, but I think that is too conservative. We may not see it yet because no one has cut the price yet, but I believe this gen will be bigger, for 2 reasons. First, most people believe that all 3 consoles will "survive" until the end this gen, cuz all 3 consoles has a unique "niche", so that means we won't see a struggling Gamecube this time. Second, what really makes the total market bigger is that a lot more casual players are brought in this time. You all know the Guitar Heroes & SingStars and see what Wii is doing, and for example EA and Ubisoft have recently said they're going to focus heavily on casual titles, not only for the Wii. MS talks about broader demographics all the time. There'll also be similar stuff to the "training games"  we see for DS, Ubisoft will release a game that will be huge called "My life coach". That's only the beginning. So I'd say at least 35 mill/year, perhaps even 40 mill yearly 2008-2010, which would give a total of 195-210 mill by 2011.

- Related to the above you have "the conquest of the living room". I just wanted to remind you of that and it's impact on sales and competition. The internet-connectivity is (or will be) a big thing this gen, which will not only broaden the total market, but is a factor you have to specifically look at when judging the competition between the 3 consoles. I believe the X360 has a huge advantage here with XBOX Live, which is already extablished and has a good word-of-mouth factor going on.

Don't stare yourself blind at last gen. Yes, everyone knows that the PS3 won't dominate this gen, but what I think people hasn't realized yet is how incredibly huge the difference to last gen is:

 - Even Sonys own approach this time was different. They used the PS3 strategically, to push Blu-ray and win the HD-movie format war by including the pricey blue diode in the PS3. Basically this decision benefits Blu-ray but so far has been a huge disadvantage to the PS3 (and probably always will be, cuz soon the PS3 won't even be the cheapest blu-ray player around, so movie freaks will buy stand-alone players instead).

- Last gen PS2 had a whole year head start, but this time it's the other way around - so that's essentially a difference of 2 years between Sony vs MS.

- Exclusive games. Last time Xbox only had Halo and Fable while PS2 had tons of them. Again, it's the other way around: you all know X360 got GTA 4 & DMC4, and how the FFXIII-exclusivity is being watered down by Square making the whole FF-franchise so widespread that it practically don't matter very much if the core game FFXIII will only be on PS3 (smart move by Square btw). What's left? MGS4.. perhaps (I doubt it). Then look at X360, what it will have in the coming ½-1 year, which will be a very critical time (I picked a few examples here):

X360 only:
Forza Motorsport 2
Mass effect
Halo 3
Lost Oddysey
Blue Dragon
Fable 2

On X360 & PC: 

Age of Conan
World in conflict
Alan Wake
Bioshock
Elveon
Huxley
Warhammer online

- All the bad press the PS3 has got is a huge thing. People don't associate the PS3 with the "hip" Playstation brand, they think of an expensive good quality console that Sony made into a disaster. People know the machine has potential, it's just that no one wants to buy it today. People don't want to take that risk, and as the experts say, a $100 price cut won't make a difference, while a $200 price cut by Sony is unlikely. 

- MS will hit the PS3 with a near-lethal blow pretty soon. The talks from MS-officials about a "sweet spot at $199" is no accident. A X360 price drop will come soon, and my personal prediction is that it will happen just when we're about to go into the fall season august/sept, when the X360 can get a huge momentum all the way through the holidays with the flood of big titles coming out for X360. I believe MS will boost that with a cut of the Premium to $299. It's logical and very smart. PS3 don't have any big exclusives this fall, so whats their incentive to cut price? Can they counter with anything? Yeah, perhaps something that will look like a desperation-cut.

- Of course you all know of the Wii-factor, how it changed everything this gen, so Im not going to argue about the greatness of Wii, nunchucks & casual games, Wiimotes & bowling games etc - everyone is very aware of it.

Why would you stop counting last generation sales just because new consoles are out?  I mean GC and PS2 have made significant inroads into Xbox marketshare since 2005, and you will probably see that again at the end of this generation when the company who is in second place but has momentum wants to build on it...PS2 is going to end up with 120-125 million consoles sold, GC will probably stop right around 22 million (only selling maybe 10-15k a week worldwide), while Xbox sells under 1500 worldwide per week I imagine.  When you throw the numbers together you get a 175 million unit generation, 184 million unit generation if you include Dreamcast.  That would mean 170 million is either a year or more too short or a huge decline in sales for the industry. 

You have to go beyond 2011 for this generation I think.  PS3 if it sells at least what it is selling now when big games come out, will only gain momentum when the price drops.  If Gamecube or Xbox had cost what PS3 does, Nintendo and Microsoft would have been completely ruined in the industry, so the fact that PS3 won't be mass market price (read: under $200) for 3 years (at least), means that PS3 will have to be supported longer to curtail whatever Sony loses.

 you just explained Sonys 10 years of PS3 talk!

Nah, PS3 will be alright..but in comparison to PS2..they still will meet with dire sales consequences for launching at such a high price.

Sound the alarm, its the doom and gloom. FF13 does not matter sure bud how about you step back in to the real world ok. Yet if they said FF13 to 360 you be saying its over PS3 is doomed. Its like with MGS4 ohh its sucks is nothing it wont help the PS3, MGS to 360 rumor ohh Ps3 is dommed they lost the best most important exclusive Ps3 cant win with out it balhh blahh.

What Sony has

Also rumored for 07 are Killzone, MGS4, and something Gran Turismo.

Why is 200 unlikely, the success of their games divison and Blu-ray depands on it. Core is not a big seller, it gets a small minority of all 360 sales.

"PS3 don't have any big exclusives this fall" thats some priceless Fud.

Gamecube significant inroads into marketshare since 2005? Ok fine, you go with your extended last gen thing (I wanted to catch the essence & dynamics of last gen, and that's when there is decent competition in it, marketing for it and so on), and just ignore arguments about what makes this gen larger then.

Do you realize you just put in a golf game in there? I never said PS3 is doomed, so dont put words into my mouth. But I do say Im pretty sure it wont start moving in 2007. The unlikelyness of a $200 price drop of PS3 was not something I made up, its an analyst prediction that Sony won't be that bold and drop it $200 this year.

Btw, your list included titles that won't come out in 2007, so could you please name the big exclusives for 2007 for PS3? Cuz I say that PS3 can't counter Forza2, Bioshock, Mass Effect, Blue Dragon and Halo 3, all of which will be released during the summer or early fall (& all of which will sell 1mill copies in the US alone, except Blue Dragon which might sell no more than 1 mill world wide).

ps3 exclusives definetly this year:

Lair
Heavenly Sword
Warhawk
Folksoul
Ratchet and clank
Home
Uncharted
+ more i cant think of at the moment

does anyone know or can predict what games will be released in 2009-2010? =))

so then, how you people can predict sales by that time? =)