Well, I can tell you that it gets pretty frustrating at times.  If you don't have any previous UNIX background I can tell you that there will be a pretty high learning curve.  However, once that's done and over with it gets pretty good.  Right now, I am using Linux-Mandrake 8.0. This current distro is pretty good from what I've seen so far. During installation it detected all of my hardware.  I had a problem with previous versions detecting some of my hardware which has made me kind of leary in delving into the OS. However, it's going well now.

As far as what is the best distro to test out is concerned, I would have to say that is a matter of preference. I think Mandrake has one of the most user friendly installations though. According to US Linux market figures, Mandrake has 33.8% of the market, Redhat has 30.7%, Suse has 23.8%, FreeBSD has 5.6%, Caldera has 2.5%, and so on and so on...I guess the best thing about these OSes is that they're all generally free.  Mandrake also has a Lnx4Win option to where you can load Linux in a Windows partition and not have to deal with the usual pain of going through partitioning a hard drive. If you don't like it then just delete the folder in the Windows directory. Info on that is at http://www.linux-mandrake.com/en/lnx4win.php3