Im suprised
that so far no one has mentioned that Ubuntu/Kbuntu are the same OS. The difference is in the widow manager and desktop. I have Ubuntu installed on a desktop, but there are several KDE apps I prefer (k3b, smb4k) so I installed a full kde desktop. In the past I have installed XFCE and blackbox, so I have my choice of 4 different desktops when I log in (using the session button). As long as you have at least a 5 GB partition, you should be able to install both KDE and Gnome under Ubuntu or Kbuntu. My impressions overall are that KDE is more configurable, but some of the settings are buried in weird places, Gnome either has a setting in an obvious control panel, or its text-file hacking time. KDE seems to handle wireless better, or at least smoother then Gnome. The kde wireless tools seem more robust. I tested this on a dell laptop with an intel wireless card which just worked after install, and with the 7.04 live cd. Honestly, I use several desktops at different times. I have a light blackbox I use when playing Postal or NeverwinterNights. I use Gnome as my daily desktop for my desktop, and KDE on my laptop. I run Ubuntu in a vm on my laptop (need XP and certain windows only apps at work.) and when I full screen the VM window, you would not know it was a VM. The hardware support for VM images built into the processor, as well as dual core technology, makes VMs run at near native speeds. Of course, It helps that VMware lets you dedicate a disk or partition to a VM instead of limiting you to a file based "hard drive", this speeds up access times a lot.
And if you could find another 512 MB ram for your test server, that would make a good VM sever.
If you have not used linux since Debian Woody, I really, really recommend you look into it again. Debian Etch is very nice, it has a similar feel to Woody, but all upgraded and clean. (I set up a Squid/Clamav/Squidguard web filter and proxy for a 5 station call center using Debian Etch. They NEED to access the internet infrequently, so an old 900 Mhz celeron with 384MB ram works just fine, of course I set it to boot with no gui by default, and disabled all non-necessary services (that I could find-a linux God I am not)). Ubuntu flavors are good, but the default security model needs to be tweeked. That goes for Mint Linux as well. which is based on Ubuntu, but has a few distro designed control panels that are quite nice. PC-Linux OS is popular, and would be a good choice to try out, and while your at it, look into PC-BSD. Shoot, for testing purposes, you could install a ton of distros on one hard drive, giving each a 5 to 10 GB root partition and sharing /boot /home and swap across distros.
