Upgrading HDD on MacBook Pro

I'm looking into upgrading the hard drive on my MacBook Pro. Since gradually building up my Lossless music library it's looking more and more ideal to upgrade my hard drive. I currently use an external hard disk drive at University but this is solely used to run Windows XP (for Windows-based apps) and to back up my whole system.

I have been using Time Machine for back up and have just read in another thread, of which chebby replied to, recommending some software called SuperDuper! if I was to upgrade my HDD would I be able to install Leopard onto the new HDD and take advantage of SuperDuper! by transferring all my files and system settings?

I would just buy another external hard drive but it's a pain in the *ss keep plugging it in, and Time Capsule is quite a bit more expensive...

Any thoughts welcome, and thanks chebby for the recommendation.