The Reasons
I love Vash for many different traits he possesses. (Did I spell that right?)
1) He's adorable.
2) He's hilarious.
3) HOW COULD YOU NOT ADORE HIM?
He's the most likeable anime/manga character I've ever come to know.
He's so cute!
He may not be bishounen material, but he ends up in my list of Best Bishounen.
I'll add more on our donut-loving, peace-making, doofus friend when I get more time. ^^