This post was originally written in 2004; I’d now recommend using MPC-HC, an improved fork of Media Player Classic.
Does this program look familiar to you? It may well do, because it’s rewrite of Windows Media Player 6, except it’s open source and released under the GNU GPL, and doesn’t have the annoyances of MS’s original. The interface is similar but a little more up-to-date and XP friendly, and comes with some more advanced features.
But probably the best thing about this player is the range of formats it supports. It’ll play just about anything you throw at it, whether it’s an MP3, an Ogg, a WMA, even a QuickTime file. And with Real Alternative (which Media Player Classic is bundled with), you can add RealMedia files to that list, negating the need for RealOne Player, which has to be enough reason to download it in itself.
You can also (probably) ditch QuickTime while you’re at it, since MPC doesn’t take an age to load, doesn’t annoy you with an ‘Upgrade to QuickTime Pro’ popup and lets you view movies in full screen. Unless you have iTunes installed in which case you’ll need to keep it.
Media Player Classic is available on its own from SourceForge but I’d recommend also installing Real Alternative and then deleting RealOne Player, since you won’t want to use it anymore. Anil found Real Alternative about the same time as me, and came to similar conclusions, so you needn’t just take my word for it.