Another vote for Tuvok. I get the impression that Tim Russ gave us the most "Vulcan" Vulcan we've seen, and although he was rarely given the limelight, he did an amazing job in conveying emotions of a character who keeps them very well hidden.
I like Tom, but Tuvok just edges him out.
Also - Tom only had a food fight with Neelix. Tuvok did the sensible thing and strangled him (repeatedly I imagine) in the holodeck. Bonus points for him