I don't know if anyone has mentioned this before but I'm sure some of you have heard of a little company called Introversion Software who make some fun games. What's more impressive though is how they use vector (I think?) style maps.

If you ever get the chance, check out Defcon. The world map uses an awesome default colour scheme and looks really slick. I've used a similar palette in some modern/sci-fi maps I've played with.

Anyway, the latest thing they seem to be working on is a game called Subversion. If you check out some of the screen shots (like this one here) you can see the really cool internal building map they have.

Just thought I'd mention it. There seem to be a lot of in-game map styles that could be adopted for use as maps on their own. The Metroid Prime 3d map is one I tried emulating once, though didn't turn out great, but worth looking as if you ever have the time or inclination (it's basically a wireframe room by room map).