TOS: Spock. He invented Vulcans as we know them. TNG: Data. He's as Vulcan as he can get without having pointed ears (sounds familiar...) DS9: Odo. He's the tough old loner who takes his security job very, very seriously. VOY: Either Tuvok or the Doctor. Tuvok is a great Vulcan and security officer. The Doctor just has a personality I like. ENT: Malcolm Reed. He's the shady-past security officer. Generally, I like either dry, boring logical personalities or security officers.
I've only seen episodes from the TOS and TNG so I'll just throw in my 2 cents with those. TOS: McCoy - Cranky, emotional, and funny as hell. Perfect foil to Spock. My favorite scenes tend to be the ones between Kirk, McCoy, and Spock. TNG: Worf - Awesome character. I like the episodes that center around him the best. I like his struggle with being a Klingon in a non-Klingon world much better than Spock's struggle.
TOS - Scotty - The man got things done. TNG - Worf - I just love the guy. DS9 - Sisko - The Sisko. The true badass bald captain. VOY - The Doctor - Picardo was brilliant in this role. He was the best part of the show for me. ENT - Porthos - The most sympathetic character on the show, because of the cheese problem....
I love how Sisko shaved his head just in time for Worf to get onboard, so that the Klingon would feel right at home serving under a bald captain.
TOS: Uhura. She was my idol when I was a kid. She was smart, pretty and had a good job. Everything I always wanted. TNG: Picard. Has his flaws but turned out to be an alright guy. He took an arrow in the chest for what he believed in. A real man. DS9: Quark. Whatta guy! A greedy Ferengi with a heart. Gotta love him. VOY: Never watched it. ENT: Phlox. Billingsley rocked that role. Best actor of the group. Overall favorite: Picard. A man of steel with a soul, and yes, a heart. Still love him to this day.
Star Trek: Kirk. The greatest space hero of all time. Smart, cool and a devil with the ladies. A fierce warrior and a cunning diplomat. The best of the best of the best. TNG: Worf. The only human being on the show. DS9: Jadzia Dax. She's so very,very hot. VOY: Holodoc. The only character on the show period. ENT: Trip because he was a real trip.
TOS: Spock (of course) TNG: Picard DS9: Kira (had to think about this one; another day, who knows?) VOY: The Doctor ENT: Trip DS9 was the tricky one here. So many contenders it was hard to choose.
TOS - Spock TNG - Data, with Geordi a close second DS9 - Odo (favorite character of the franchise) VOY - Tuvok, with B'Elanna a close second ENT - Hoshi nuTrek - Pike
TOS - Spock (favorite character overall) TNG - Data DS9 - Garak, if we can pick non-main-cast characters; Kira otherwise VOY - EMH ENT - Trip nuTOS - Spock. And thus the circle is complete.
TOS: McCoy, and this goes for XI too. TNG: Actually, I don't think I had one partially because I held most of them in the same high regard, and that's a plus for the series. I can't say the same about Troi or Wesley, but hey, let's stay positive. DS9: O'Brien, though Bashir was cuter and Garak is Garak VOY: Tuvok was pretty cool. ENT: Sato
ENT: #1 Archer / #2 Trip TOS: #1 Spock / #2 Kirk TNG: #1 Data / #2 Worf DS9: #1 Garak / #2 Ezri VOY: #1 The Doctor / #2 Tom
Tough question. TOS: Spock, but very closely followed by Bones and Kirk. TNG: Data closely followed by Picard DS9: Just can't decide. Kira, Sisko and Miles for sure, but there are so many good characters on this show. Too my great surprise I'm really starting to like Ezri since rewatching season 7. VOY: Janeway (Seasons 1-4, she gets a bit mean after that) and The Doctor. ENT: Not a fan of this show, but I remember Trip quite fondly.