[http://www.activestate.com/Products/Productivity/ASPN_Komodo/ Komodo] from ActiveState is a rich IDE for Python, Perl, and XSLT. It is really good.
The current version 3 is in Beta (as of July 4, 2004) and pretty solid. I suggest you grab it while its available. I expect the Beta will be good enough to use that you may not bother upgrading - especially for hobby use. Check the license agreement.