Favorite is any black rock instance that I can solo with my 70 prot warrior.

Most favorite is Strat.  I think a prot warrior is one of the few builds that can solo the entire place and kill everything.  nice drops and the orbs sell for 40-50 gold each.

least favorite-any instance that takes way  way  tooo long because someone in party has gone afk for food, beer or whatever and you have to stand around saying Hey where are you
/rw HEY  come back on.