I'm planning to make an audio workstation out of my IBM T60P type 2008 with Fedora as the primary distribution. What studio distribution or other solution would you recommend for me and how much hard disk space should I reserve for it? I have some experience on Linux, but I'm no jedi, so...

I previously had a desktop computer with XP and Steinberg Cubase - don't remember the version. I've pre-produced couple of albums with that solution. But the computer is now broken beyond repair and on the other hand I have much better laptop - at least on paper.
Oh... and one more question! What USB sound cards do you recommend for Linux audio workstation? I'm not sure what to get but minimum requirements are two mic/line inputs. If you have some advice on a card with more inputs - like Presonus Firepod - I'm very interrested to hear your experiences too.
Thanks in advance!
EDIT:
And info about the computer
IBM T60P type 2008
Genuine Intel(R) CPU T2600 @ 2.16GHz
3 GB memory
256MB ATI Mobility FireGL V5200
100GB Hard disk