Or, do what's very trendy in Web design right now and buy a Macintosh. The Mac OS has had a ton of usability research done for it. It is widely considered to be the most user friendly operating system out there (while not intending to start a "my favorite OS" flame war ).
It isn't that having a Mac makes you better at designing, it's that many designers are taking a que from the Mac OS in how they design things for the Web. Google is your best friend here. Start searching. Start experimenting. A List Apart is a good place to start.