I thought it would have been interesting if they'd have gone with Paris, since he's inaccessible in a way that Chakotay isn't. It would also add something to that Seven/Torres frenemy rivalry thing they've had going on. Not only would Seven be taking Janeway's attention from Torres, she'd be stealing her husband. I would have rather had them go the comedy route and have either Barclay or Kim be her "tutor" in all things romantic. If you're looking at the characters, I'd say the Doctor is her best match--they both have the "outside looking in" thing, and she made the parallels herself in the episode where Janeway wanted to wipe his memory (whose name, ironically, I have forgotten!).