Hi blackhawk,
me think there is no rule which keywords should be highlighted in which special color.
Just do like you want, maybe take an existing color scheme as basic to get some ideas.
There are some web pages displaying colorschemes for various languages, used by Textmade and VIM, take that for more ideas.
http://textmatetheme.com/
https://code.google.com/p/vimcolorschemetest/
BTW, the highlight colors [1], [2],… can be defined in the [Display] tab as Highlight (1), Highlight (2),…
>>>” I don’t want to customize this for one language and then have all the rest look like crap.”
If you utilize “Tools > Properties for Current Configuration”, you will work
only on the settings for one syntax highlighting profile. The other languages are not affected then.
HTH?
( BTW, I answered your question one hour before you actually asked it [see posting timestamps] :D )