I have a large client with an entire TV production staff. We have been publishing in WMV for months with no complaints. We provide instructions for non-windows people most of whom already know how to handle wmv because it's so popular.
In a recent meeting however, we began exploring mpeg for downloadables and Flash for protected content.
(Funny though, these media people wanted to publish in ALL formats. When explained the process (time) and the cost of bandwidth and disk space, they agreed that we either stick with wmv or one other alternative.)
From experience, I would suggest that if you're publishing wmv files for download, zip them to force the download, otherwise people will play the clips in place and you'll chew up more bandwidth than you may have intended.
I'm about to put a dedicated box in place just for media files. It seems the web is making that transition I expected, from text based to media based. More and more of the larger players (especially news) are making the transition. Throw in some pod-casting, Internet radio and interactive Flash and you have the interactive TV of the future.
I wrote an article a few years back that the Internet is the TV of the 50s. I'm confident that within the next 10(?) years it will be difficult to discern the difference between your T.V. and your Internet browser. I remain convinced... we are on a path to true multi media.