Seems to me that the need to periodically connect and charge a keyboard (or swap batteries) would be much more hassle than a fixed cord, especially for a keyboard that's dedicated to a single PC and left on a desk.
I once owned a wireless Logitech DiNovo keyboard and grew to hate it for that in addition to the sucky scissor switches.
Now, for a multimedia keyboard to use from the couch? Bluetooth for sure, but I don't personally have a need for it right now .