Deleting windows font which were copied from my bootcamp partition I recently wiped my os x partition to reinstall a fresh mountain lion. I already had windows xp installed as a bootcamp partition, and it seems os x copied windows font (tahoma, verdana, surely others...) to /Library/Fonts/

They now appear in webpages, and for example Tahoma does not look that good, and I'd like to this not happening.

Is it safe to just delete them ? Do I need to rebuild the font cache after this ?

I once remember that just after installing bootcamp + os x, os x asked me if it could copy those font, but it just did without asking me first.
You can turn them off in Font Book without deleting. Open the Font Book app in your applications, scroll down until you find the troublesome font and right click/secondary click on it and select "disable font".

Alternatively, problems can often arise if you have duplicate fonts like where osx has installed both the windows fonts and it's own fonts. In this case you could also try right clicking and selecting "resolve duplicates".