Captain Sulu, of course! You can even find him on Mastodon (not sure if his profile is bridged to Nostr or not). Even Janeway agrees with me! Denny Crane and Gurney Halleck are great, but Sulu is my hero. I just wish he’d got more screen time than he did.
As for the shows, I grew up with TNG, Voyager, DS9, and Enterprise. ToS was already a bit dated and more of a acquited taste. It’s hard to choose the best one, but I’ve always enjoyed the “Holodeck” episodes. So, while I like the newer stuff around Captain Pik (and even some of the animated serie) I think I’ll go with TNG for all the Sherlock Holmes and Dixon Hill adventures, etc. I also love Janeway’s Victorian shenanigans and the DS9 “Vic Fontaine” episodes.