Which derivative of Ubuntu should I use? If I'm running XP, bash I have to partition my hard drive?

I would recommend installing either Ubuntu or Kubuntu. They some enjoy very nice GUIs. You shoudl just shrink your C wall so that you have nearly 10 GB of freed space for the UNIX install; that should give you plenty of room all for the initial lay and then some space all for storage.

I do not believe Ubuntu will be competent to run Windows applications short ALCOHOL setup. GNOME and KDE are just 2 different types of GUIs, you should scan some pictures of them online to see which one suits you.

Ubuntu is all very easy to setup a dual boot, it basically does everything for you and you can then easily boot into either Windows or Ubuntu.