in reply to Regex Hell
If you have to do email addresses without a module I'd recommend looking at Friedl's solution.
Friedl is the author of O'Reilly's Mastering Regular Expressions and seems to know his stuff to a quite remarkable degree, this email code is explained in the book if you want to know more about what's going on in it, and more about regular expressions in general.
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Seekers of Perl Wisdom