My advice would be stay away from bluetooth. From my limited experience blue tooth never had good range, as other said it would fall asleep to easily. As such you do not see near the ubiquity that blue tooth should have recieved.
Just stick with logitech or other companies wireless accessories that use RF and come with their own dongles. In addition so much of the content in the next couple years is moving over to being able to use wireless lan connections IE WiDi. And even when it does not support that there is also someone making something that works over the network.
My next question would be how much gaming do you plan to do on this machine? Or I assume that is what you are building it for, also what type of games. Because for most of your web browsing and what not any smartphone / tablet you have will work just fine, and you will not need a keyboard / mouse at all.