During last evenings I have updated a little bit my vice-versa project.
Since vice-versa aim is to bring in every browser what is possible to implement and, in most of the cases, already defined as standard (from W3 or MSDN when it is worthy) I decided to get rid of the Ariel Flesler fast trim proposal to introduce my lightweight full specs String.prototype.trim, trimLeft, and trimRight.
For full specs I mean that vice-versa String.prototype.trim replace exactly same characters replaced by native Firefox 3.5 implementation, rather than only characters which code is less than 33 as is for Ariel proposal.
The good part of vice-versa ( to be honest I cannot find bad parts so far ;) ) is that every single file is stand-alone, so if you do not like benefits the entire "lib" could bring, you can always adopt only one of its files, for example the String one, the Array one, or the last full specs ECMAScript 5 Date constructor, compatible with ISO strings, new Date("2009-07-10") and with a complete toISOString method for each created Date instance (of course even if replaced, new Date will produce instances of Date and their constructor will be Date itself).
If you want to give vice-versa minified a try, a little monster which size is about 5Kb gzipped, please do not hesitate to download it.
Have fun with future standards and few MSDN standard coolness for every browser ;)