TOS: 'Bones' McCoy (for his dry wit)
TNG: Jean-Luc Picard (for his Shakespearian acting, great morals, great dialogue)
DS9: Ezri Dax (she's just cute, chaotic, lovely) Also Elim Garak, genious. Gul Dukat, brilliant. Weyoun, Jeffrey Combs is just good.
VOY: In reality NOBODY was really good on that cast and more than not did they annoy me. The Doctor was probably the best character... and he's a Hologram.
ENT: Tough call really, nobody really leaps out, T'Pol was a fine Vulcan, Archer was an ok captain, but Shran was really the best character (yes, Jeffrey Combs is just THAT good).
STXI: Zachery Quinto a.k.a. Sylar a.k.a. GabriŽl a.k.a. Spock probably the best character there.
TOS - Nurse Chapel <3
TNG: Umm... *blanks out*
Enterprise: Hoshi, with Mirror Universe T'pol being a very close second.
DS9: Ezri Dax
Voyager: *blanks out again*
Alternate Reality (star trek XI): Tie between Uhura and the Orion cadet girl.
Enterprise: Archer... mmm Scott Bakula... *drool* hehe
DS9: Sisko - Avery Brooks *_*
Voyager: EMH - I loved his personality.
Alternate Reality: Bones... his rant about alien diseases made me love the actor for such an acurate portrayal of Bones. <3