Go with XP. I have been running XP Pro since it came out both at home and work. My work computer I have only had to reboot once for a problem with the OS. And given my profession, a programmer working on home automation control systems, that is just amazing. Otherwise it stays on all the time...
Goto www.dvdchanger.com. They still have a handfull of changers left. It is connected via firewire. The software is clunky but hey you can load 200 dvds.
Rabi