Kneeling, naked in bondage works for me :P
There are many others I like a lot though, such as face down, bottom up(whatever that one's called), strung up in some sort of suspension, either right side up or upside down, splayed out haphazardly over a railing, furniture, debris etc.(think ragdoll physics in video games) and quite a few more, but I'll stop.
Laid out with her panties in her mouth is really excellent too.
Alright I'll really stop :P