We often get asked for suggestions on video and audio input devices for PC or Macs. Here is a list of some capture cards that work well:
Elgato Game Capture HD - $150 range - Has its own built in encoding software.
BlackMagic Intensity Shuttle - $190 range - Can be used with Wirecast / Adobe Flash Media Live Encoder software.
Hauppauge StreamEez - $245 range - Has its own built in encoding software - This also does all the processing of your stream within the device, so it can be used to save processor resources but it does require to be plugged in via usb at all times.
Here are some higher end devices that do all the encoding outside of the PC / Mac environment:
Cerevo Liveshell Pro, LiveShell 2 - $299 - $450 range - Higher end built in h.264 encoding. Will not require to be plugged into a PC / Mac to stream.
Teredek Vidiu - $700 range - Higher end h.264 video encoding. Will not require to be plugged into a PC / Mac to stream.
If you have any other suggestions or success with other capture cards please share them with us!