If you like loud obnoxious metal music, gay CG explosions, "heroes" who are drunken lay-about sleaze mongers who have absolutely none of the characteristics that make us feel empathy and/or sympathy towards them and villains who seem to have no world-conquering motive then you'll love Iron Man!
Seriously... is it just me or is part of what make the great superheroes great the fact that we can relate to them on some level? Even the high and mighty billionaire Bruce Wayne has an extreme vulnerability that makes us side with him when he's battling villains but this Tony Stark prick has absolutely no redeeming qualities whatsoever!
Sure, it makes him suave, cool and "macho" but it also makes him a gormless fool who I frankly was hoping was going to be blown up in the opening moments of the movie. He'd probably have made a good bad guy for Spider-man, actually! I'd have been on his side then, if the drunken fuck-headed Tony Stark was battling it out with the Amazing Spider-man then maybe I could have been like "That Iron Man kicks ASS man!" but I'd probably just have been hoping that he was played by Willem Dafoe.
In short, Tony Stark/Iron Man was a hero for people who don't really like super heroes, in my opinion. He was a sort of "Die Hard" action hero character who, in that setting, we can all side with because he's bad-ass, doesn't give a fuck and doesn't stop till all the bad guys are dead and everything around them has blown up.
So let me add to my opening statement:
If you like piss-poor heavy metal, dumb-ass explosion-riddled battle sequences, alcoholic dead-beat heroes and you don't actually like super hero movies, you'll love Iron Man.
And if anyone tells you this film was better than The Dark Knight (Especially if the person telling you is Robert Downey Junior) then kick them hard in the nuts.