Tatooine and Kashyyyk are -tedious-, except they have HK-47 and Jolee, respectively. Manaan is actually pretty fun until you get to the underwater facility and that -obnoxious- part where you walk at about 1/8 speed through an overly long passage. *Bwaaaaaaaugh* Dantooine isn't bad, but it has huge dull stretches of empty space, and Taris is, well, Taris. It's not as bad as Peragus, but it's close.
So yeah, Korriban.