If you have a spare hard drive, you could download the Windows 7 DVD (as an .ISO file) and install it in your spare drive without requiring a Product Key. That will let you try it for 30 days before a Product Key is required.
I have a Win 7 DVD that I downloaded but cannot recall the site I got it from. Try this one click here
I went from XP to W7, and ran a "dual boot" for a few weeks.I soon ditched XP and have not looked back.I even kept a clone of my XP for a while. My advice would be to run the MS Windows 7 advisor, and if all is well, go for it!