Aha, my laptop is similar to your computer, though a bit weaker. I have:
Intel Core Duo T9400 CPU 2.53ghz
Geforece 9300M GS 256
4GB RAM (but you know laptop memory)
I use mine almost exclusively to play GOGs though.
Diablo III runs barely acceptably on minimum settings. Most areas are fine, some are extremely slow. Your gfx card is better than mine, so would probably look smoother on yours. I have made it to Hell Act II and lvl 56 thus far so it's playable, but not ideal.
I think Starcraft II worked acceptably as well.
WoW runs rather well actually.
Sorry, not offering a lot of variety here. I use my laptop a lot since I'm abroad often, however I use the opportunity to replay classics: Deus Ex, Civ III, Tex Murphy, Gothic II, Arcanum, Fallout 2, etc.