<p>Does anyone use have a good regex library that they like to use? Most of the regexes that you find online either contain bugs or are so focused on the edge cases that it turns into a competition to validate whatever spec 100%. Of course you can write your own, but when you are billing by the hour its handy to have a library around. </p>

Besides being pretty much the best Regex tool on the market (seriously), RegexBuddy is about the only tool I know of that lets you switch amongst different Regex rendering engines.
http://www.regexbuddy.com/
See info here:
http://en.wikipedia.org/wiki/RegexBuddy
RegexBuddy's proprietary regular expression engine allows the software to emulate the rules and limitations of numerous popular regular expression flavors.