For me, beauty in a programming language is when an idea can be expressed simply and elegantly, doing something non-trivial in less lines than one would expect.

The new Higher Order Perl book by Dominus has many good examples. There's a recursive Tower of Hanoi solver in about 15 lines, a directory walker with hooks to plug in your own functions, and many more examples.

People who think perl is ugly have probably been using it as a slower C, instead of as the elegant, powerful language it is.