Best file format (video) (not sure if this is right thread)

Hello all

not sure if this is in the right thread (if not code someone move it pretty please).

Whats everyones experience of file formats for video on line.

i’m building a site at the moment and need to be able to put video samples up to show. now i was leaning towards flv but my client has heard wmv and then the whole conversation on what we should use came up.

Just wondering what you lot thought on this?