I am most looking forward to all the new animations/abilities that really make each spec feel different from each other, especially Enhancement Shamans.
My fondest memory of wow would be a little after TBC launched my guild ran me through UBRS while lvling my blood elf pally because I never hit 60 during vanilla wow. It was the first time I have ever got on vent with a guild and was the start of a great relationship of that guild all through TBC and Wrath.