I am planning on buying a ps3 sometime this year along with a kick-ass HD TV. I am getting 3 or 4 games to start . I think I will be buying Uncharted 2 and Gran Turismo 5, so I may have room for two more. The only thing I want is that this games were long, replayable and good online multiplayer.

Thanks for your ideas...

Long?

Demon's Souls is rather long.

honestly it really isnt that long, my first my play through took about 40 hours.....and most of that time was from me throwing my controller and walking away for like 30 minutes at a time and about half way through my first run i had a panic attack and reshaped my character so i had some unneeded grind thrown in .   Each new play through only takes like 7 hours for me now...

40 hours is really long in my book lol

If your just getting a PS3 then you have to get Uncharted 1 and 2. Also if you like Racing pick up Motorstorm Pacific rift which will get you a lot of play offline, and online.

Modnation Racers, White Knight Chronicles, Killzone 2, and Final Fantasy 13, because well... its FINAL FANTASY!

uncharted 2 is a lenghty single player game (by today's standards that is) with a decent multiplayer component.

valkyria chronicles also has a meaty single player campaign.

I haven't played it yet, but demon's souls is meant to be pretty long also.

Infamous is another one, especially because you can play as 'good' on one playthrough and 'evil' on the next.

Demon Souns, Valeria and Infamous cant go wrong with any of them.

Folklore.
An oldie but goodie.

Killzone 2's online multiplayer will consume you.