A bit more trollish than how I'd say it, but this pretty much the reason a lot of people doubt the sales of GTA4. GTA has strong appeal to gamers (as in 2-4M sold appeal), but it's appeal to people who don't normally play games is utterly peerless. Some of Nintendo's stuff on the DS is pretty close, and Wii Fit might beat it, but GTA is still the reigning king of the casual hill.

How many of those people have a 360 or a PS3? How many of them are willing to pay 400€ to play the next GTA?

Obviously fewer than 15M, but the big question is how many fewer. 

GTA:SA last week sold over 11k units in NA, i also doubt people are just buying the one GTA game when they have that GTA trilogy for the same price. So thats about 30K GTA:3 series games being sold each week, along with the LC and VC stories this game is massive and will continue to sell until the next gen systems die. GTA4 should blow passed 11mil with ease ones the dust settles.

It is going to be a special game. I reckno in terms of graphics and gamplay

Yeah I think that's a very good prediction. It's hard to tell. On one hand, the userbase is smaller. On the other hand, there's probably more hype for this game, and both companies will be pushing it through bundles or price cuts and advertisements. 11 million is definitely possible, and very probable.

Though zackblue, 25 million would be crazy, since even GTA:SA was short of that by 10 million.

My predictions would be about 11 million. 6 million on 360, 5 million on PS3. I won't break down into regions.

Nice job counting bundles. Whatever. The fact is the last 3 GTA games have sold over 11, 14, and 16 million counting multiple versons on both consoles. More if you count PC. I think it's clear that now GTA is the best selling game franchise. San Andreas and probably Vice City surpass every Sims game and all but 2 pokemon series. The recent pokemon game was outsold by other games.

GTA is the best selling game franchise?

The Sims sold 17M.

StarCraft sold about 15-20M, I believe.

Pokemon Diamond and Pearl was outsold by other games. So what? It still beats the GTAs.

Seriously, BT and MBT have sold 22M in total. BT is going to outsell GTA:VC at least, and probably GTA:SA. And hey, Nintendogs? It's beaten it, and widening big time.

OT:

Facts: GTA:SA sold 5.5M in its first year, out of an 30M install base on Ps2. This is USA only. It launched 25th april, so that get's pretty much the same. It ended up selling 8.6M so it sold 63% in its first year.

If we then say Europe sold 55% in its first year, since Europe is more leggy, we get 3.6M meaning GTA:SA sold about 9-10M in its first year, out of an a bit bigger userbase. 11M is possible, but I'd bet 8-9M.

EDIT: Way off! Sorry! 8-9M in 2 months, not 8. And the userbase was also a lot bigger, 77M. And it didn't sell more than 800K the next year for USA, so let's say 9-10M first 8 months, out of 77M.

This one has 48M base.

If GTA does sell that well Take-two would have beem right not to sell to EA

I think 11M are possible, but not this year. If you look here: http://vgchartz.com/games/index.php?name=grand+theft+auto&console=&publisher=&genre=&keyword=&order=Sales That says, three versions reached 11M in the past - in lifetime sales. All three was on PS2, a console that had a bigger userbase, than PS3 and X360 combined. At the moment. So I think 11 M are possible, but not this year.

I see GTA4 get at least over 10 miilion sold.

I have a small problem with 5 million on PS3. Look, there are about 10 million PS3's. Even if half of those 5 M buy a PS3 with GTA4 it will have around 14 million MAX consoles sold. This will mean an attach rate of over 33%! I don't see that happening, partly because the price is still quite high for ordinary people that don't really care about games.

i don't think GTA4 will hit 10mil this year

losing the casuals is gonna hurt sales

eventually enough hardcores and enough semi-casuals will get the ps360 to push sales above 10mil, but not this year imo

u'll see like 6-7mil in first 2 months and then only another 2-2.5mil the rest of the year