I was playing this game religiously before Modern Warefare dropped, then Fallout 3 hit the back burner and I stuck to MW2, NBA2k10 and Fifa. Needed to get my RPG fix and I went back to it. I have GOTY edition btw. And the first time playing through I had no idea what the hell was going on, I just did whatever to my hearts desire and got a little entertainment out of it.
I went evil the first time I played, and since picking it up again I'm taking the good path. I'll go back and do evil again, because I really shit the bed on that file doing too much, too soon and ruining some good parts of the game (Ten Penny Tower, namely). So this time around I'm taking my time, and doing side quests and just plotting along. And I'm really enjoying this game.
I was one of those guys that played Oblivion a few times through, so I could see myself doing it with this game, maybe once I complete it with my good character I'll go back and start an evil character and of course get them both through the DLC.