What are you trying to do, melt my brain?
This is much more difficult than the average question found here on Yahoo Answers.
Let's examine some of our options.
Wolverine: Arguably the most popular character among the fanboy set. And why not? Wolvie rocks. Adamantium claws make you cooler than Lou Reed and that's not easy. But, is Logan the best? Probably not. His James Howlett backstory was just too lame. We waited almost thirty years for a mystery to be cleared up and they gave us a bomb. So, no, not Logan.
Spiderman: Marvel's most recognizable hero is, indeed, awesome, but is he the best? His life is a mess and he's been trying to atone for a mistake since 1962. That's hard to beat. Now, in the wake of House of M, he's mourning for a son that no one else even knows about. Poor Peter Parker can't catch a break. I've got to say, though, that Spidey did teach the world a valuable lesson. With great power... This is important stuff. So, I'd say that Mr. Parker is in the running for best character.
The Hulk: Man vs. himself notwithstanding, Hulk smash a little too much. Not the Hulk.
Thor: Thor is awesome the same way that your crazy neighbor lady with the pink flamingoes is awesome. So, no, not Thor. (Ultimate Thor has a much better case, but not him either).
The Silver Surfer: Still hanging ten after all these years, but not Norrin Radd.
The FF: The FF taught us about tolerance and family while kicking ass at the same time. That's pretty hard-core. So, maybe the FF.
Dr. Strange: The good doctor put his arrogance aside and now defends the world from some of the creepiest baddies in the multiverse. Sadly, he dresses like such a dork. Not Doc S.
Captain America: I like Cap, but the political climate of the world right now prevents me from getting too behind the man with the shield.
Iron Man: Brilliant, rich, drunk, Tony Stark is the man. I know he doesn't drink anymore, but he's still a fat-cat, so not Tony.
Cyclops, et. al., I love the muties, but probably none of them.
I'm going to have to go with Spiderman, as he has taught us some of life's most important lessons, and instead of merely speaking these lessons to us, we have had to learn them through his pain and from his difficult life.