Growing up it was Batman. I was in 4th grade when the original Batman movie came out (by Tim Burton with Michael Keaton and Jack Nicholson) and I loved it. Then I started getting into comics and I really loved Nightcrawler and Spiderman. Since then I have really come to love Superman.
So overall, my 2 main faves would have to be Batman and Spiderman (DC and Marvel respectively), but some honorable mentions are...
Superman- All around great character
Nightcrawler- Just plain cool- especially in X2
Wolverine- 6 Adamantium Claws...what more can you say.
The Green Lantern- Someone who can make anything out of a glowing ring is cool in my book.