I used SciTE for a while. It uses plain text for configuration so you might like it since you don't like XML. I never wrote a syntax highlighter with it but I hacked the C++ one into a javascript one and it wasn't that bad. That was years ago though so I might not be able to help you much.

On the whole though, I think that it's usable but sucks. Quit worrying and learn to love the XML. I hope I don't get an infraction for trolling for that last sentence