But not nerdy enough to dodge Vista and get a stripped-down, OEM copy of XP pro....
Vista sucks ass (Vista user here)
I'm getting tempted to try Linux, but worried about application availability.
I dual boot, like Nittany does. Personally I have Vista and Ubuntu. When I was filling out all my Navy application stuff I found myself using Windows a lot. I had to use Internet Explorer for the security clearance and didn't trust OpenOffice (the open source, Linux-friendly version of MS Office) for my forms. There are ways to run both of those in Linux, but it takes some knowledge and work.
Part of the reason I use both is because Vista runs slow on my laptop. I also just like linux for everyday stuff. It's secure from viruses and adware, smooth, looks good, runs fine, is free, etc...
Basically, unless you have a reason to change, it might be more trouble than it's worth IMO. But, it's easy to try so giving it a shot couldn't hurt either.
EDIT: As far as Bubba mentioned about viewing files between operating systems, there's a driver for Windows that shows your Linux partition and Ubuntu picks up my Windows stuff just fine.