All of the above? Pretty much all of the above for me. Maybe not too flexible though, or else it's just a pain to mess with. Lady Lambada is SUPER flexible -- even has a backbone thing -- and it made it impossible to even use really.
I like a small curve or straight for thrusting. Tender Touch Spiral, Sweet Lola & Lia G Bliss are my top favorite toys to thrust with! Love them! I have the Pure Wand and find a curve that drastic to only be painful.
I like Tender Touch Spiral for thrusting (it is a straight vibrator) because it works great for cervical stimulation & I like Sweet Lola for its G-spot stimulation when thrusting & Lia G Bliss is just incredible all over for thrusting!