Key factors to consider before choosing your bitrate:

Target audience download capacity: Consider the projected download speed of your target audience. Generally, a viewer should have a download capacity that is 1.5 times greater than the stream's bitrate. If your audience primarily has dial-up, broadcasting at a higher bitrate will be counter-productive.
Your upload capacity: If you are streaming live, make sure your upload speed is 1.5 times greater than the stream's bitrate.
Bandwidth Consumption: Broadcasting at a higher bitrate leads to greater bandwidth consumption per user.

Bitrate Comparison Chart

Included below is a list of common video and audio broadcast types and their recommended bitrate in kilobits per second (kbps). Note: Many bitrate choices are available. The following bitrates are meant to act as guidelines only.

Audio
Voice only
AM radio	20kbps	This is an excellent bitrate for broadcasts that are primarily talking.
Music
FM radio	32kbps	This is the current industry standard for FM radio broadcasts. It will work well for any music broadcast, or as a higher quality option for voice broadcasts.
Higher quality music	64kbps	Using this bitrate will provide a higher quality broadcast that works well for delivering near-CD quality music.
CD quality music	128kbps	This is generally the highest audio bitrate you should use. It will deliver excellent quality. Note: You should compare a 64k broadcast to a 128k broadcast, as many people do not feel the slight increase in quality is worth doubling their bandwidth usage.
Video
Static image (e.g. a person speaking at a podium)	128kbps	This should generally be the lowest bitrate that is used for video. It can be used in situations where significant movement is not expected.
Standard Video broadcast (e.g. conferences, concerts, instructional video, etc)	282kbps	This bitrate is the current internet standard for video broadcasting. Most viewers on a high-speed connection (DSL, cable etc.) can effectively view these broadcasts.
High quality video broadcast (weddings, sporting events, racing, etc)	548kbps	This bitrate will provide a higher quality broadcast that is often preferred by people whose broadcasts contain a lot of movement or action. It is also an alternative to 282kbps broadcasting if you want a higher quality. Note: Some viewers may have difficulty watching your stream.
Very high quality broadcasting, fast action video, high detail video (sailing, car racing, etc)	1128kbps	This level of broadcast is necessary for high quality broadcasting of fast moving events, and can also be very effective for situations that require a high level of detail. Often broadcasters will offer this in addition to a lower quality broadcast.
DVD quality video	2137kbps	A very high quality stream that would be most effective for a specific audience capable of streaming data at such a high rate.