Jeff "Coding Horror" Atwood beams about his La Crosse Technology BC-900 AlphaPower battery charger, which as chance would have it is the exact same battery charger I purchased a couple of months back at all y'all's suggestion, but haven't actually yet had a chance to use, as my AA usage mysteriously has dropped to next to nothing.
You can also switch between four different readouts after the mode is engaged: time elapsed, voltage, and two mAh (I assume one is charge/discharge rate, not sure what the other one is). That refresh mode is incredibly slow-- it's basically discharging and recharging over and over-- but it really works. It can take marginal batteries from the brink of death and give them new life.
But you don't have to care about any of that; if you just drop 4 AAs or AAA batteries in the device, it will charge them fine. I spent several hours after I got it plugging various batteries in it, trying different modes, and watching it work. I'm not sure what the exact definition of geek is, but I think "enjoys recharging batteries" has to be very high on that list.
Adventures in Rechargeable Batteries [Coding Horror]