Stay away from the Logitech bluetooth. I've had a lot of trouble installing their software, ending up using my own bluetooth USB stick and Windcom that comes with XP and uninstall the Logitech straight away.
I had to pair the mouse and keyboard every 15 min, cause running out of memory (1024 RAM) all the time (the software must have a leak somwhere).
Before that I had the wireless one which is good if you don't keep your mobile phone near by. Runs out of batteries very often tho.