When I encode movies myself, I use DivX...if you can't view those correctly, you need to get or update your DivX codec. At least in the past, I've had trouble even then, but if you get the DivX Player and use that to open .AVI files, they'll work no matter what. If you can get DivX files to play in Windows Media or whatever, even better.
When you see movies in other formats on PGC (like the WMV of Rainbow Six 3 that I posted today), that's in the format in which it was provided. I don't have the video editing know-how to decode such files and recode them in DivX...and I don't think the video quality would be very good, either. So if you're annoyed that we keep offering videos in different formats, that's simply because we get them in different formats. As I said earlier, any video that I'm encoding myself will be in DivX. It's pretty much the best quality for the best file size.