1. The hair. There is no such thing as a "bad hair day" for anime characters. I could also have weird and wild hair... hair in an unnatural color or in a style that defys the laws of physics. I tried spiking my hair up for cosplaying Vash...
It just wasn't going to happen. Of course, there is much more fun hair out there - Yugi hair, Jessie/Mushashi from Pokemon hair... I rather like Integra's (Hellsing) hair because it's all long and flowy.
2. The eyes. No, I do not want bigger than normal eyes - I just like the variety of eye colors anime characters get. In Neon Genesis Evangelion, for instance, two of the characters have red eyes. I'd love to have freaky, blood red eyes.
3. You can spout philosophy without people thinking you are a dork or overly weird or boring (usually). You can get the BEST quotes!
4. No matter what you eat or how much, or how much exercise you actually get, you will have a perfect body.
5. Assume now that your body isn't completely "perfect". Say you've got scars. Well, folks, those scars on your anime self will... look really cool. (Okay, so I'm a bit weird... I like scarred anime characters). Vash looks good with his scars (I think), I like Misato's big body scar, I think the scar over the eye of Anderson from Hellsing is cool.. and I find Jet (Cowboy Bebop) very cool looking for that metal thing he has going on over his eye.
6. When you get angry, you can have scary flames rise up behind you!
7. Sweatdropping rocks.
8. No matter how much blood you loose, or how many times you get "blasted off", you will survive.
9. Your actions as an individual really CAN change the world!
10. If you do have a death wish... you will get a really cool death scene, and often a really cool song to go with it.
11. You get cool animal companions or really cool animals... just randomly show up. Personally, I'd love to have Yakul from Princess Mononke... or a penguin like PenPen from Eva... or that Daddy Cat from Azumanga Daioh!
12. You don't have to be a human. If you are in anime, you can be the member of some mysterious, non-human yet humanoid-looking race, the product of a weird genetic experiment, or maybe even a cat-girl or cat-boy. Or maybe you are just an android who wants to be human. That's cool, too. I would like to truly be able look at the human race from a non-human perspective.
13. You get to weild cool weapons, perhaps even weapons of mass destruction. Personally, I'd just like something simple, such as a cool, magical sword.
14. The use of said weapons will come as an instinctual talent. (Take mecha-piloting).
15. No matter what you wear, the weather does not bother you. Take being scantily clad in the snow, or my favorite example... long flowing capes and trenchcoats in hot, even desert conditions.
16. If you revel in angst, you are cool, and not just an obnoxious whiner - IF you don't overdo it.
17. You could get cool appendages. If you are in a futuristic anime - parts of you could be cybernetic! If you are in a fantasy anime, you could get something else. I'd love to have cute little Haibane wings! (Though, if I had wings... I'd seriously like ones actually capbable of flight). Haibane wings are still cool, though, because they're cute.