You can add on snippets, syntax coloring, et al. Really lightweight solution, loads quickly etc. Of course, it is not an IDE, so no debugger. ActiveState Komodo has a good debugger and you can use it for both Perl and Python.
Wow. I was just writing a message like "TextPad is dead, don't use it", but I've checked the site and it looks like they've released v5 after all these years :p I wonder what new features (if any) it has...
Btw, I recommend Komodo.
I bought a license for TextEdit 4 a few years back, but although it is fast and nice to have around, I never really loved it. I also switched to OSX at home recentlty and haven't really found a text editor I like, though JEdit comes closest. It is cross-platform and has a few useful plugins for perl, but it works best with a big screen. My MacBook's screen isn't really big enough for it if you a lot of plugins.
How can you feel when you're made of steel? I am made of steel. I am the Robot Tourist. Robot Tourist, by Ten Benson