Mine would be a free spirited, outdoor loving, adventure seeking, intelligent, rational, reasonable, creative girl. Also attractive, I'm shallow.
Appearance isn't that much of an issue as long as she keeps her self healthy, doesn't wear too much make up (none preferably) and has soft features. Mentally though, she would have to be open minded, extremely intelligent, have non-worldly goals (I wouldn't want someone whose main goal in life was to be a business exec, banker, politician, etc.), down to earth (as in being laid back and friendly, but also very earthy, aware of her impact on nature, and has a deep respect of the earth that borderlines worship), and a good cynical sense of humor.