One of the most common questions asked by newcomers to Linux is "Which is better, KDE or Gnome?" The answer commonly given is, "It depends. Try them both and see which one you like best." It's a reasonable answer, because it costs nothing but time to try them.
The same answer is given in articles with similar titles to this one. Again, a reasonable answer. I won't be giving you that answer. I'm going to tell you which one is better.
My first distro was Red Hat 7.2, and the default desktop manager was Gnome. I was happy enough with it, then I changed distros to Mandrake (now Mandriva). Mandrake's default desktop was KDE, and I thought I'd give it a try. After using it for a while I found I liked it more than Gnome. It was more configurable and customizable. I could select which applications I wanted to open for all different kinds of filetypes instead of the miserable choices of email and web browser that Gnome gave me. There were also way more options for customizing the desktop and windows.
When I plugged in my iPod KDE would let me choose to open Amarok automatically, or any other program I wanted. Gnome opened Rhythmbox, and only Rhythmbox. In order to get it to run Amarok I had to delete Rhythmbox, write a small script that launched Amarok, and name the script Rhythmbox. Then when Gnome tried to run Rhythmbox, it would actually run my script, which would run Amarok. It was an ugly kludge.
KDE also let me do "pretty" things easier. I could run Xplanet as a background using KDE's "Use Program" option in the background selection. You had to use a script for Gnome, and it never worked the first time, and you had to go to forums to figure out why, and you finally decided that it wasn't worth it. Well, maybe not you, but me.