I was hoping someone would put this up!
John Debney - What can I say? He's a great composer. Just listen to 'The Big Fat Kill' from the Sin City soundtrack. Absolutely amazing. I also love his take on the Inspector Gadget Theme (even if it was a bad film!)
Danny Elfman - Another talanted composer. The way he does it with energy and fun (like MIIB and Spider-Man) is just great. I especially love his main title theme music for Spider-Man 2. Now, THAT'S how you do super-hero music!
John Williams - The best of the best. He has done some really wonderful music, and it shows. Harry Potter (the first three films), Jaws, Indiana Jones, The Terminal... I have to mention The Terminal! It's probably the best work he's ever done!