(wow. and i thought there was nothing left to say on this topic! :) SIZE
ryan, SIZE has not yet been mentioned in the thread-- glad you mentioned it. with superfish, at least, the extra !important rules have no noticeable effect on my page-load time, in IE, firefox, or chrome. page-performance is important to me, so if the stylesheet was so huge that performance suffered, i WOULD take the time to find and apply ! important only to those specific widget-rules which really need veto- power. i think load-time is more of a concern with javascript, not css. at the moment, even with all those !important rules, superfish loads faster than my png's (and they ARE optimized). jQuery compressed, on the other hand, is 10 times larger than my css. these are the files required by superfish: superfish.css (with !important on every element): 5K remaining superfish files (such as images): 13K jquery-1.2.6.min.js: 55K perhaps your concern about size comes from your javascript perspective? i think this response effectively answers the 'size' issue.
