I would highly reccomend you try a Live! CD before you try fully installing it. You might not like it, and you may become frustrated. Also, when you install the full verison, be sure to make a partition so you have access to Windows via GRUB.
Ubuntu is a really nice OS, as it has many cool auto-scripts that installs most multimedia functions, WINE, etc.
Kubuntu is basically Ubuntu running on KDE, not Gnome. Many people use it for the eyecandy. But if you want eyecandy, you might as well use OS X.
For servers, Suse is your best bet. That or FreeBSD, but that isn't Linux.
http://www.freebsd.org/
For personal use, Fedora Core and Redhat are both great.
If you want a complete replica of Windows version of Linux, Linspire is for you, although it is commercial.
Once you get experienced, try googling Debian.