Deevey has hit the nail on the head. Develop your production style, then buy a controller that allows you to d that more efficiently. Using a mouse is slow - but once you know what it is exactly that you want control over, choosing a controller will be easy.
Before buying a controller, learn the key shortcuts - this will speed up everything you do 10 fold.
I agree that learning the keyboard shortcuts is a great idea. The keyboard covers that are widely available for Live's commands are great for this.
Originally Posted by Patch
"if you don't know what controller you need, you're not ready to use a controller".
This is a very conservative view. One has to start somewhere, and he's an adult who can spend his money however he chooses.