Hello neg,
In terms of performance Ubuntu has been always a real top dog, if you look at phoronix.com in many different bench mark testing Ubuntu usually comes out on top. However if you are looking for something new maybe give Arch Linux a try, generally in my experience Arch Linux is the fastest I have ever used but does require time for setup and future maintenance that I did get tired of maintaining that setup and just moved back to Ubuntu. If you are still interested in the other distributions here are my thoughts, fedora is the best representation of the gnome desktop, openSUSE offers Windows users some familiar system and user management tools with YasT and Debian is great for stability and longevity but will feel a little behind the times as packages are a little out of date.
In most cases other distributions are based on other main distributions but I see no point in mentioning or ever using as they rarely do any other work then lay there own custom skin over the top of something else.
I need to do more research with Django before I comment on that however if you got it running in Ubuntu generally will work in any Linux OS at that point. When I find out more I will comment back on that subject.
EDIT: So I did some research on Django and seems to be well supported on most distributions from Ubuntu, openSUSE and Arch Linux, Fedora documentation looks like it is 5 or 6 years old and would not tempt it with those. If you simply type into a search engine "how to install Django in Ubuntu" you will see plenty of guides.
Looks like Django is in the official Ubuntu repository which means it could be installed via terminal or software center however it is Django 1.3 and it looks like they are on version 1.7. So you will find instruction how to install from downloading the tar.gz from the site. If you need any help with that then just let me know.