As much as I love the magic mouse, its not for gaming. I would suggest something like maybe a logitech or razer mouse.
And for diablo 3, I;ve given up on it. Blizzard is getting annoying with their ridiculous development timelines. I know their excuse is "Quality takes time" and its true to an extent but other companies are able to pull of excellent games in a reasonable amount of time.
Annoying as Blizzard's elusive and time-intensive projects are, D3 looks awesome and their Friends and Family beta just started! Closed beta starts within a week and the game is still out for release before 2012!