Personally, I'm not big on them (and not just on the pictures, in-game as well). What slightly saddens me is that the Worgen Cat Form is something I feel to be almost mandatory when playing a Kitty just because it looks so awesome in my eyes. Whereas I still think my Tauren Bear Form is the best thing every to tramp upon Blizzard's green earth.
Still on the fence about the Troll forms, Ill have to check them out in game to see if they grow on me or not. BUT, Worgen forms are, for me, everything i LOVED about the Tauren forms and what I had wished the NE ones would have been. The Worgen forms are enough to make me reroll my 80 NE Druid.