Movie - Nemesis. I think anyone who has seen it would agree.
Voyager - "Fury" ... I was looking forward to seeing the return of Kes, but this episode ... ugh. Ms. Lein must have seriously needed the money after she read the script. That, or she signed up to do it before she read the script. Whichever it was, the episode stank out loud. When Voyager came out on DVD and I did a re-watch, that was the one I didn't watch. Haven't seen it since it aired originally, and don't plan to make the mistake of tuning in again. I'd rather watch a random episode of Enterprise than this crappy episode.