There's not really anything on my planned site that would require a whole lot of customization but I'm looking for something that has built in functionality for forums, comments, reviews, a blog, a database that can queried by users, and some social networking features.
I have a decent amount of experience using python so I was thinking of using Django and also learning it in the process.  I realize though that this would be much more time consuming than using a CMS.
So, part of me is inclined to use a PHP based CMS like worpress or drupal.  I don't have any prior experience with PHP but since all the features I'm looking for are built in, do you think this would be my fastest route to get up and running?
Drupal or Joomla are your best bet. Firstly, Joomla allows you to basically drop in these features you're asking for in an install an go manner. This is the easiest way to go.
Now if you want a LOTS and LOTS customization and don't mind getting into a little code then drupal will be perfect.The great thing is that the customization possibilities are almost endless! The bad thing is that Drupal has a NOTORIOUSLY crazy templating system. It's not hard to understand but even simple things can become a real pain. But Like joomla you can avoid all this with install and go plugins. you'll have the choice.
I don't know too much about wordpress, but having looked at the developer API, it seems to assume volumes about what you intend to build on top of it. Which makes it a lot less flexible than drupal and django.
Django, well according to your question... it's everything you don't want. Also if you have gone to any of the Django CMS sites you'll see how painful it is to get them up and running. That said I'm personally a Django fanatic but I'd rather you dint run into a bad experience with it and have a horrible impression of it. so given your question i'd say Drupal!
CMS or web framework a simple project