Partitioning some of drive for old OS + other for storage?

I have a 160 gig hard drive that i want to keep, its XP with everything I like on it. I plan on buying the hitachi 2tb but i am using my 2 drive bays already. Is there any way to partition 160 gig on the new hard drive for the old operating system and the rest as another drive for storage? will it limit the space? I am running windows 7 on a seperate 80 gig drive if that makes any difference. Thanks