Underrated: Star Trek: Enterprise. It's not top of the line Star Trek by any means, but there are some stand-out characters among the main cast and guests. I think it suffers from a few key problems - 1) the theme music is jarringly non-Star Trekish, 2) it bogs down a bit in the Xindi storyline which dominates too much of the time, and 3) it wasn't distributed in syndication. Trying to anchor the UPN with it, I think, limited its reach. The prior 3 Star Trek series had all been readily available to me on one of my local channels through syndication and ran a full 7 seasons each - but by being UPN which was carried locally on a weakly transmitted CW station meant I couldn't watch it.