Which Playstation3 is better?

They are the same except for the memory.

They are the same besides the memory size. I’d recommend the 120GB. It’s what I bought. It saves you about $100 and 120GB is quite a bit of space on the PS. If you were talking 360s, I’d say go for the bigger but with the PS, 120GB is plenty. If you can find a 1st gen model PS3, one that’s not a slim then it is backwards compatible with PS2 and PS1 games.

Game recommendations: Red Dead Revolver, Metal Gear 4, Demon’s Souls, Call of Duty Modern Warefare 2, Uncharted (1+2), Assassin’s Creed (1+2), Grand Theft Auto 4, Killzone 2.

They all have the same amount of memory (~512 MB I think). The only difference is the storage capacity of the hard drive. I have the older 80GB version and am running low on space. If you plan on putting extra media on the PS3 like music, pictures, and movies you might want to get the 250GB version.
As far as game recommendation: Fallout 3, Call of Duty (World at war or MW2), Red Dead Redemption, GTA 4, and Valkyria Chronicles.

The one you leave on the store shelf.