Snape/Harry/Draco is my OT3... but if you only get one, and it's gonna be full of filth and multiple kinks, I think Snape/Lucius/Remus has the best chance for threeway hatesex; nice canon arguments can be made that none of them likes each other at all.

Oh, and I don't think I've ever heard of Lucius/Remus. I like the idea of some Snupin, some Snucius, and then something takes Snape out and Remus & Lucius are stuck together (until he gets back, and then the three of them can have nasty betrayals-all-around buttsecks.)