Depends how detailed you want to go, ER.

For BI, RTW and MTW you could have:

- Best models
- Best 2D art
- Best textures
- Best animations
- Best video
- Best music
- Best voice audio
- Best coder
- Best scripter
- Best non-roman-era historical total conversion mod
- Best non-historical total conversion mod
- Best enhancement mod
- Best roman-era mod
- Best gameplay
- Best balance
- Best support
- Best tool
- Best in-game text
- Best attention-to-detail
- Best (most realistic) battles
- Best map (aesthetic)
- Best map (strategic value)
- Most promising mod

And so forth. It might also be interesting to allow people to vote for their "favourite" mod rather than a "best". Voters may, for example, know that a certain mod of a certain genre is exceptionally well done but they will vote for another of perhaps a little less brilliance if it is in the genre they like, By saying "favourite" rather than "best" the vote is more accurately reflected I think. Indeed, the word "best" could be replaced by "favourite" in all the above.

I am not sure categories should be established where there is no real way for a person to know the truth of the matter: Best dev. team for example.

Just some quick thoughts.