I don't agree with Joe on that. I guess that he was looking for Keyboards that were capable of working as a free standing instrument with built in voices- as an electronic organ or a stage piano, for example.
For midi work on a computer, it is more usual these days to use sounds inside the computer rather than in the keyboard.
Accordingly, all you need from your keyboard is the facility to turn key presses into midi messages sent via USB.
Nearly all of these controller keyboards come with USB, and are much cheaper.
Here are some examples on Musicians Friend
Cheers
Dave