I just downloaded GTA 4. I only ever played GTA 1 before this and I figured, meh, why not. I may get 3 as well. I had to buy a 360 controller for my PC though cause the laptop keyboard and mouse are hard to use on a couch. Last night I just hooked the laptop up to the tv and played on there.
If they do bring 5 out on the PC I'm doubting my laptop will handle it. It seems to run 4 well but I played some other game and it lagged horribly.