I'm not sure what you mean by "relevant", other than "title fights or title-contender fights", but...
1. Fedor vs. Overeem
2. Mousasi vs. Hendo
These have been named already, so maybe they're too obvious, but I think they have to top the list. Maybe we should just all name our Top 7, and put these two somewhere in there.
3. Rampage Jackson vs. Rashad Evans. This might earn the winner a title shot, possibly depending upon who wins Machida-Shogun. Lil' Nog is knocking on the door too.
Belfort and Marquardt appear to be next in line, and I wouldn't want to see either of them in an elimination fight. With Dan Henderson gone and Yushin Okami forgotten, Bisping, Akiyama, Maia and Sonnen appear to be next in the depth-chart, so I propose a UFC Middleweight mini-tournament.
4. Michael Bisping vs. Demian Maia and
5. Yoshihiro Akiyama vs. Chael Sonnen
If the two winners can then meet, great; if not, the most convincing of them could be given a title shot in the first quarter of 2011.