I prefer F/M (as you might guess from my writings), but enjoy all of the other combinations if well written. A near exception to this is the spanking of children of either gender, but I say "near" because in a really loving environment even they can be appreciated.
LawnDawg:
I guess I am not looking for reality in my stories, but an escape from reality.
Agree completely, but would add that escape from reality--suspension of disbelief--requires that the author write well enough to build a convincing, internally consistent story world. This does not necessarily require a lot of detail. A masterpiece can be painted with a single stroke of the brush (though not be me).