This + QT Lite and Real Alternative Lite will do pretty much any format you'll run into.
Dude.. NEVER install realplayer. It's not worth it. Ever.
Just install Real Alternative if you really get stuck with rm/rmvb/whatever-shit-only-works-with-realplayer formats and you can play them easily in vlc or whatever other player you like. It even handles the real media content in browsers.
Same goes for QT Lite to handle any Quicktime content.
(I am sure that there must be similar workarounds for Linux as well.)
This might be a bit late, but I'll post it anyway.
You can use another program called QT Lite. It provides the same functionality as Quicktime, but does not include a movie player. Works fine with EV Nova.