The =~ returning the matches in an array context is probably also one of my favorites. Note that you can also combine it with the g modifier, like this:

@array = ($string =~ /(\d+)/g);
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to get every number on the string. In fact, if you have a simple regex like this you don't need the grouping parenthesis, you can simply use:

@array = ($string =~ /\d+/g);
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One of my favorite examples of this is the following code to keep the $VERSION variable in sync with the RCS/CVS revision number (taken from the perlmod man page):

$VERSION = do { my @r = (q$Revision$ =~ /\d+/g); 
                sprintf "%d."."%02d" x $#r, @r };
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It took me a while to fully understand this code the first time I saw it :-)

--ZZamboni