Hi,
I have just installed Studio this morning actually!!
Studio doesn't need a separate install. It's basically a load of packages that are in a separate repo, split into 3 main categories of Graphics, Video and Audio. I installed all 3, and it took up about an extra 1.5gb i think but my linux install is quite a large one, so it might take up more for you. I really only wanted the audio, as it gives a low-latency kernel which is great for audio and video editing.
You also get extra art work and stuff, but that's all a bit surplus to requirements. It basically includes all the best audio, video and graphic programmes available for linux today. Defo worth the install for the low latency kernel and JACK if you've got the space.
The website was down, but is now back up, so just follow the instructions here
http://ubuntustudio.org/downloads and scroll down to the part about the ubuntu studio repo
Good luck .