There is an older post on this topic that really was not answered. Where can I find out what media players people are using?
[websiteoptimization.com...] media player user trends, broadband penetration and more for 2006; links to more sites for facts
[macromedia.com...] Up to date facts about Flash penetration by version
Quicktime comes on all Macs; PC's come with Windows Media Player. Flash 8 is about 65% as of Q1 3006 In our tests with all 3, Flash downloads significantly faster, Windows Media Player was the slowest to start.
But i think that these are very rough estimations. Can somebody tell what is ViewPoint Media Player? Not used in Europe I think, at least not in my country.
When you are making format decissions you should also consider what is your content and who is your target audience. For example flash video is good for advertising purposes. On indie short films site I would use QuickTime as main format.
Flash Player doesn't include external player which can be issue in some cases.