Unless you get ProTools 9 you are locked into specific Digidesign-approved hardware (copy protection)
Cubase is cheaper
Reaper (REAPER | Audio Production Without Limits) is only $40 and you can spend a LOT more money on equipment.
The difference between ProTools and Cubase is workflow. You can go to any Barnes&Noble and read through the manuals to see which one 'clicks' in your head;that's how I chose Cubase. But then I went to Reaper and never looked back...
