Of the major characters:
1. Han Solo: Sexy, suave, handsome, and capable. Plus, he's got a great ship!
2. R2-D2: Love the plucky droid! Can't believe R2 didn't make more lists!
3. Vader: For reasons everyone else would likely state.
4. Boba Fett: Love the strong, silent types.
5. Palpatine: Lots of love for the man who rose through the ranks to run an empire.
Of the lesser known characters:
1. Kit Fisto!
Have figures of him all over my desk.
2. Asajj Ventress
3. Prince Xizor
4. Admiral Thrawn (I love the Chiss)
5. Max REBO! Blue elephantine ortolans make me smile.
(Okay..this became much longer than it should've been, but there's just so many characters I love that I didn't want to leave anyone out.)