I gotta go for Alderaan. And even though I haven't seen some of the others yet, I don't think they'll beat Alderaan. Mountains, snow, blue streams, roaming nerfs, wildflowers--add to that the cute medieval-style music, the royal 'houses', the awesome taxis, and that really nice cantina with the outside balcony--I want to vacation there! It's definitely a resort place. Even the 'cocktail' they sell at the cantina is called 'Holiday Special'. (Good stuff, by the way.)
I'm hoping that there will be an update that maybe adds in a ski slope game there. Or maybe a speeder slope game.
When I hit level 50 with my smuggler, I'm letting her have a holiday on Alderaan for a bit, just exploring things that I might have missed. Maybe I'll find something surprising.