i give an ok to strings and pseudo classes like :hover and so on, an ok also to !important and such, but i think its way too early to switch the highlighter to css3 completely, after all, its still not here
about browser independent extensions, i give a completely no-no, the main reason is that if you support one browser (firefox in your post), other browsers must be supported too (ie, opera, safari/khtml, ...) or it wont be good enough, since when you try to make something for one you try also to make the same for the other browsers as well if they support it (an example would be -moz-opacity in ff / filter:alpha in ie) -- <http://forum.pspad.com/read.php?2,33915,33928> PSPad freeware editor http://www.pspad.com
