Gaybucks did a great job at the answer...

Whatever method, file, or codec you choose something else will come out the day you get them all done that will temp you to do them all over again.

We use Digital-Rapid's encoder cards with Streams Pro software for higher end encoding. Because it has video and audio chips that can take the pressure off your computer it can do a bit more with a bit less.

The fun part is that have released some good codecs for Flash. Since you are not broadcasting flash files "LIVE" you don't really need a dedicated flash server even they are are great to have.

In the long run I still feel that .wmv will become better as they finish up on some codecs they are working on. What we have seen looks really good.

Besides the bitrate always remember that a lot of people still live in dial-up or slow DSL areas. If you to streaming in either .wmv or flash you may limit your users.

Keep working on it. Your videos will look great in HD.