Komodo(!)

[Kee Nethery]

 From the web site it looks like the free version does not include the  
debugging stuff.

I've been using the paid version with the debugger functionality and I  
find it easy to use and incredibly nice for trying to understand what  
the code is doing. The built-in debugger has saved me tons of time,  
especially when troubleshooting CGIs.

I'm using a Mac and of the Python IDEs I looked at, Komodo had the  
easiest to use user interface, in my opinion.

Kee