While I'm not 50 just yet, I use;

Flash
Featherfoot
Internal Release
Second Wind

I plan on keeping second wind for two reasons. 1, I think it's that much more you can do to help the healer. Granted it's not much but can be a lifesaver in a sudden emergency. 2, from what I've seen on provoke, I don't find it necessary for another single target (at least my impression was it was single target) aggro since just by using the Skull Sunder/Butcher's Block combo I can build all the aggro I need.