i think ff15 will come out in 2012/2013. though i hope its multiplatform.

Well at the rate it's going, I don't expect the PS3 to catch 360 for overall sales at least until end of 2010 or during 2011. It would be unlikely that the PS3 outsells the 360 by at least 8 million in any year AND it would obviously have to match the sales for the year it does as well (which, being pessimistic, means at least 6 million). Obviously that means it won't happen over 1 year, and it hasn't even started yet (360 still outselling PS3 in most weeks recently). So, it'll require an extended period (especially if Sony doesn't want to waste precious money on price drops any time soon).

Where am I going with this? I believe that come late 2010 or during 2011, the PS3 will be within striking distance of the 360. Potentially surpassing it by the end of 2011 (Though chances of it doing it and not doing it are almost identical imo). Now, OP assumed that a single player FF (so 14 if it was SP) until at least 2012.

By that stage it'll be (I hope, for competition sake) an all out war between the 360 and PS3 to take a strong lead (for 2nd place). At this time, a Final Fantasy main series game, exclusive to either platform would be monstorous. Even without exclusivity, given FF's appeal in Japan, this would be a massive ace up the sleeve of the PS3. It won't be what turns the tide to the PS3's favour (if my prediction is correct), instead it'll be the Sony's silver bullet to the 360. It will extend the lead of the PS3 at that point, potentially making a gap that can never be made up (with the generation running out of steam and all at that point).

Also, given the state of MMO's in the post-WoW era, I don't expect any MMO to be a massive bonus for any console. Remember, FF11 was around 2 years before WoW. So taking that into account, it was able to establish a loyal fanbase and keep a certain amount of people due to their investment into their characters. In the post-WoW era, I doubt it can reach the same success, especially given the fact that Blizzard seems to be churning out expansions like clockwork. If they don't launch a new one this year, they will most certainly launch one next year, how can anything MMO or even PC related compete with that?

I'm not to sure how FFXI and FFXIV will coexist (can you transfer your characters over or are they two separate worlds?), how many do you think will move over to FFXIV, especially if FFXI continues? and how many would prefer the PC version over the PS3 (or even 360, if it exists)?

Well, remember for mmo we pay monthly subscription and probably we'll have to pay for the expansions. So, it needs a permanent team to work on it, but in other hand they have something like 20 dolars from each player per month plus 60 dolars yearly from the expansions, and if FFXI haven't made at least as much profit as a common FF they wouldn't realese another MMO FF.

^^  Interesting, Calamity.  I do think there is some limited uncertainty about XIV online's sales, but I think it will be huge in Japan and very big elsewhere and that SE will apply plenty of lessons learned in XI.  I know many people for whom this game will be more of a definite purchase than a single-player game.

And while an exclusive FF in 2012 would be big, I think we must consider that PS3 sales in Japan are still quite low, and goosing those sales significantly in 2010 would have a large positive effect.  (XIII and GT5 will do this, anyway, but the more the merrier).  Addidional games will be sold between 2010 and 2012 after a consumer decides to go for XIV online, etc.  More people may even jump on XIII knowing that XIV is following soon after.

I consider PS3's potential to get MMO's very important and under-utilized, and I don't know why after WoW, other MMO's aren't supposed to be valuable.  It's almost like betting 360 would fail just because the PS2 was already out.   If you predict XIV won't have the same sales as XI, I counter-predict and say it will have more.   The HD console that people WANT JRPGs and SE titles to come out on, PS3, has had precious little of them, and demand is certainly there.

As for XI, I think SE said it'll continue and that achievements within XI can translate somehow into XIV.  XI will be heavily cannibalized, though.

2012 sounds good as an estimate for PS3 passing 360, though I doubt a single player FF will come until 2013, and may not be exclusive.  FFXV maybe PS3/NeXtBox multiplat.

Really?  Where?

Well i think FFXIV online will suck in sales like FF XI. The MMO market is oversaturated. Wow is fastly dominating the mmo market. Also with other games like Lineage 2 , W.A.R, L.o.t.R online. It will port for 360.

What's the FFXII team doing?

Isn't a large number of FFXII staff doing FFXIV?? Since FFXI staff worked on FFXII?

Btw, we have forgotten Agito XIII? >_> where is that!

Well, last generation had Final Fantasy X, X-2, XI (online) and XII on console (XI on the PC as well)
This gen, as of now, has Final Fantasy XIII, vsXIII and XIV (online) on console (XIV on the PC as well), so if the trend continues there will be a XV this gen...

FFXIV Team interviewed by IGN:

What platforms is Final Fantasy XIV coming to?
Currently the game is confirmed for PlayStation 3 and Windows PC. An Xbox 360 version isn't official, but Square Enix is considering the possibility that it could.