Supports most formats except for Real.....the various Windows Media formats are kinda touch and go...It really depends on which WM* version it is. VLC 0.8.6 has spotty support for WM9, older Win Media files work fairly well...
For Real stuff, just get Helix player.....That's about all it's good for. It works for most of the other "free" formats, but they left out MPG support for some reason....