How much battery life would you say is sucked away by using a bluetooth mouse and/or keyboard? I am thinking about buying a mouse for my MBP and I'm just wondering what the best option is. What suggestions as far as mice does anyone have? I like the looks of the logitec VX nano and the micro USB receiver, but if there is a better bluetooth mouse out there and they don't significantly drain the battery, I may want to go that route to keep the USB port freed up. So, what do y'all suggest? Thanks!