However, I recently became aware of WebStorm for some JavaScript work I've been doing and loved it so much that I'll definitely be investigating that company's Python editor as well -- PyCharm. Again, this is a commercial editor, but the licencing is cheaper than Komodo, and if it's on par with the JavaScript version it'll be a great package. There's a free trial available.
Note that as a beginner it might be quite some time before you're able to or interested in using the additional features these editors offer.
Otherwise if you're after something free I'd second (third?) the recommendation of Notepad++, which doesn't have all the fancy bells and whistles of the above mentioned editors but is a great syntax highlighting editor, and as a beginner is certainly more than capable enough when you're getting started.
: Added link.