Apart from the webpages you mention, there's also Douglas Hofstadter's book Gödel, Escher, Bach. For perl specifically, there's my Short quines.

Update: These days I also started to like quines that look like this:

print+("\\","\"",",","print+(",")[3,1,0,0,1,2,1,0,1,1,2,1,2,1,2,1,3,1,
+2,1,4,1,4]")[3,1,0,0,1,2,1,0,1,1,2,1,2,1,2,1,3,1,2,1,4,1,4]
[download]

Update 2010-01-28: These unpack quines by mtve below are nice. Here's my attempt.

print unpack a44X44a43xaXXaaXaXaxaXaX4axa, "print unpack a44X44a43xaXX
+aaXaXaxaXaX4axa, \"\\\nn"
[download]

Or, if you don't need the newline, this works too.

print unpack a35X35a34xaXXaaXaXXa,"print unpack a35X35a34xaXXaaXaXXa,\
+"\\"
[download]

Update 2012-12-12: see also General quine, Short quines.