SV650 is good for learning cause it has a low seat height and is easy to ride, BUT!
A R6 is a better bike and better for stuntin and all the chicks seem to like them and like to stunt on them.

 

600rr or r6. Both light, narrow, and user friendly. My girl rides my r6 now and loves it. I still dont trust her so the F.I. Cage is still on it. I tried getting her to ride my gsxr but she *****ed to high heaven about how wide it was. I know girls who love the zx6r/rr as well.

 

Busa hands down.

 

I love my gixxer 600. Not too big, but I won't get bored with it, either. It just had to be lowered 3 inches.