I usually look for intelligence and good looks first before I look at the body
(meaning rare to begin with), but I'd generally like a girl who's average to slender in build
(Meaning: no anorexics and no whales), and breasts that look like, well, breasts, and not sagging bags of watermelons nor the plains of Kansas.
Example of a perfect ten in terms of looks and build:
Kanna Mori (Natsumikan!)
http://media.photobucket.com/image/Kanna Mori/asuka-hero/profile_kanna-mori.jpg
Slender, has a chest, great legs, killer smile...now if only she could speak english and could converse with me on topics like the best way to balance a strawberry on top of an ice cream sundae. ^_^