Note that Gnoppix uses the Gnome desktop.
Knoppix
http://www.knoppix.com/ (a very well-regarded Live CD) used the KDE desktop. KDE has more eye candy, but it's really a matter of preference. Both have different looks and functionality so take a peek at both. While different, both demonstrate one thing clearly - that choice is important. You can choose your desktop in Linux. Gnome and KDE are the big two but there are many others.
I, too, started with a Live CD. Once I became comfortable, I started loading different distros on a separate hard drive so it didn't get mixed up with my Windows. I assumed it would be a hobby distro but I haven't looked back since and never boot in to my Windows machine anymore. Just don't need to.
I currently use Kubuntu (KDE version of the Ubuntu distro, which is Gnome-based). Ubuntu is based on Debian distro and its apt-get system, which makes it easy to download new packages. Other distros, like Fedora and SuSE (both VERY good) are based on an RPM system. You'll get to know the difference.
Once you install your distro of choice on your hard drive, be sure to set up your 'Sources' list so you can easily get a hold of the package of your choice within seconds. I use Synaptic (graphical front-end to apt-get) and Ubuntu has over 16,000 packages once you activate all the sources, which draw all the packages from online "repositories." Way more efficient than Windows, you'll find. I'm not suggesting you try Ubuntu, by the way. Try what you like and don't listen to people who say, "This distro is better than that one." It's simply a matter of preference.
This may be all greek to you now, but within a few days of installing a distro, you'll be amazed at how core pieces of knowledge like this become second nature.
Enjoy your Linux adventure and welcome to the community!
Rory
