For those of us with modest geekiness levels who are taking first steps into the world of Linux, the best plan, IMO, is to create a dual-boot system, ideally with Win XP and your favorite/chosen flavor of Linux. I've never heard of anyone except Bowser having a disaster with a live CD...perhaps it was just a coincidental hard drive failure. Many flavors of Linux support live CD, which allows a test drive without making any changes to your system. In addition, a live CD is a valuable resource.

Being the most popular, Ubuntu seems to have the most extensive set of on-line resources, and also supports a live CD. I've had reasonably good luck with Mepis (KDE desktop), but there's no 64-bit version at present AFAIK. I've also run a number of other live CDs with no problems.

This page has resources comparing X windows managers and desktops.

Here is a page comparing KDE and Gnome desktops.

For those considering a dual-boot system, it might pay to do some Googling first with your chosen Linux flavor, PC, wireless card and whatnot as search arguments to see if others are having success/problems with your particular h/w configuration. I had to bash around a bit to get my wireless card working properly, but I seldom use the command line at present. That will change as time goes on and I get my new box, which will also dual boot Win XP and probably Ubuntu.

Since my current Win XP partition is live and well, and time is not only limited, but precious, I haven't had the impetus to get Wined, but CodeWeavers CrossOver Compatibility Center gives an idea of what Windows aps will run under Wine - mostly games. As I've said on several occasions, Win XP runs my legacy software fine, and as long as I can keep an XP system alive, my computing life is jake. However, I no longer go online with Windows. Booting into Mepis for web tasks offers a a relative painless introduction to Linux along with the additional benefit of increased protection against on-line mischief.

S