Personally, I use the Linkworld LK-1000 multimedia wireless keyboards. Lets you pair one KB to multiple receivers. No lag, no missed keys, battery life has been outstanding.

Downside is I did have about 20% dropout rate for defective parts. Took me 7 keyboards to get 5 that worked.

Upside is they're $19 each at Fry's and (once you get good ones) they do work very well.