FireFox under Ubuntu Linux 10.10 with the non-free codecs does work (without a Microsoft plugin). I have not tried other distros. Ubuntu is based on Debian, so FireFox on any Debian variant should work.
Apple Safari Browser: I don't know. If you can't get WMP to run, RealPlayer might work.
Opera: I don't know. Opera has an extremely small share of the browser market.
MTV Channel 2: In case your video problems persist, try MTV Channel 2