Well since KDE is just a GUI any Linux Distribution can have KDE. With that said there are some distros that only distribute KDE.
KUbuntu - Ubuntu version with KDE Only. Ubuntu is Gnome
Yoper - Ive used it temp and didnt like i much. Had a few conflicts with installing and services and just the general feel felt messy. Not your Web Service Distro.
There the only ones that ive used there are more of course which distribute both KDE and Gnome. However just listing them from what ive used isnt going to help you.
Have you ever used Linux before? People say Linux is easy to use, and yes it is to a certain degree however depending on which distribution you decide upon you will eventually require the use of the console so if you havent used it Id suggest using Knoppix to start off with just to get the fell of linux without even installing it.
If you have used Linux what distribution did you use? There really arent that many differences to distributions if you really think about it. Some will change the UI of the GUI you chose and do some enhancements however there isnt much difference. The only significant difference is package management RPM and DEB are the most popular that I am aware of, of course Gentoo and others use different however DEB and RPM are the ones used in most distributions. If you liked the package management used by your previous experience of Linux perhaps its best to stay with it (of course theres never anything wrong with change).
Why do you want to use Linux? Well why do you need to use it? Is it for Developing Web Pages with PHP and using Apache as a webserver, general desktop usage, gaming?. To decide what distro is best because someone said it is, isnt exactly smart they may use it for a different purpose then you wish to.
