I think colors can be useful but only when subcategories have the same color (and no various shades of it, that’s useless unless you have the eyes of a professional color grader or a mantis shrimp)
As for the color choices, I would do it this way :
- General Forums : Grey, because it encompasses all kinds of topics (so all colors mixed together)
- New Site Feedback : Blue, because New goes well with Blue (I find)
- Jobs : Brown, because brown reminds of work stuff (maybe because of all the leather bags and book covers in the old days)
- Artwork : Purple, because purple goes with fantasy, imagination and is generally a playful color and not much else, unlike the others
- Coding : black, because coding is dull. I’m kidding ! Green of course ! Because The Matrix, I guess
- Game engine : I don’t know. Any color. This category may not stay here for very long anyway.
- Support : Red, because HELP MEEEEE !!!
- Contests : Yellow, because gold medals and trophies, you get it
- Misc : well… I actually suggest we do something about that category. Read this thread if you want to know.