Does anyone else find the Magic Mouse somewhat power hungry? We have had the latest iMac since July and we are already well into the second set of batteries. The first lot supplied by Apple were rubbish but even the Duracell super duper ones I have in now are already down to half power. I know I could easily use rechargeable's but they would last even less time. Our previous C2D iMac didn't eat them as bad as this new one?