Blood elf + Tuaren shams primarily

Z = warstomp
shift Z = bloodelf silence
X = bloodlust
C = Earthbind for roots (tend to use this one as a miscellaneous talent key, was stoneform on my dwarf)

For other teams I've used Z and X for things like the Draenei heal, or the undead priest DoT or Cannibalize. Basically I don't tend to spam with those keys since I use WASD for movement, but they are very accessible for things that I don't use often but need at the tip of the finger if I do need to use them.

edit - also use those slots for Paladin "Hand of" spells if I am out in BGs