Well, yeah.. you can get rechargeable AA batteries... but they aren't the same (especially compared to a proprietary lithium ion battery). For one, you don't have the luxury of being able to charge the batteries while they're inside the camera, as you do with a lot of cameras that use proprietary batteries... you have to use a seperate recharger, and that's a pain. Plus, proprietary lithium ion batteries have 2x the capacity of nickel metal hydride rechargeables and about 3x the capacity of nickel cadmium rechargeables... and when it comes to digital cameras, I think that's pretty important. Lithium ion batteries are lighter as well, and do not suffer from the 'memory loss' that other types of rechargeables suffer from (this is where you have to completely drain the battery and recharge it to full, or you won't even get full life out of a charge). After having both a camera that used standard AA batteries and one that used a proprietary LiON battery, I just prefer the proprietary battery
-Tom