New Creative Station - Pre-Purchase Concerns

I currently have a Creative Station that's about 3 years old. I want to upgrade to a Windows 7 64-bit system. My only concern is how painful this process will be and how much down time I will have. My current system has 3 hard drives - OS, Audio & VI samples. The data on these drives are not separated 100% as mentioned because Sweetwater had some samples already installed before I purchased the 3rd drive. What all will be involved in reinstalling software? My system is currently tweaked very good and I admit that changing systems makes me nervous but I need to get past that 32-bit 4-gig memory wall. Maybe I could ship Sweetwater my audio & Samples drives and have them installed when they build my machine. Any thoughts? Guessing many of you have gone through this already.