Two posts stand out so far, first being someone saying GTA4 won't offer anything new so not interested. Thats a valid point if you didn't like the gameplay style of gta3 and its sequels but thats not what he said. Most games don't offer anything new, GTA3 and VC were really very good and if GTA4 is a new story and looks better and offers similar gameplay it should be a pretty good game. A good story with any decently enjoyable gameplay tends to be good, with a great story it could be great. We get like 1 original game a year, if that, a game doesn't have to offer something new to be good. Mass Effect is KOTOR 3 but different story and its fantastic.
As for the other post, it needs a gamepad to be good so will suck on the PC. Firstly, its not a realistic racing sim, its never had anything remotely close to realistic driving and frankly cursors do a more than fine job with driving. Infact in several years of playing these styles of games I've never once had an even remotely difficult time driving in these games with cursors, not to mention theres more options for steering wheels and gamepads on the PC than on the 360 or PS3. Maybe you should have a shout at Rockstar for not implementing incredibly easy control support in the first place.
Can't say for sure but no initial interest in multiplayer support at all. Can't stand most 360 games on multiplayer so far. Far more interested in the normal single player, hoping the story is really good and they haven't done anything stupid to gameplay mechanics to make it crappy. Thought the story and , well, most of San Andreas was utter crap. Even though the whole Mafia style crime stuff is very cliche, somehow the writing is decent in most of those games. Where it comes to ghetto style gang violence every damn word is a cliche, painful to hear, predictible and crap. Bunch of older white guys hearing 10 common slang words from the ghetto and repeating them every 8 seconds, seems to happen in so many films and tv crap and then SA. Hoping the move back to more familiar settings will give us a better story again.