Hyperion DUO3 is the best. It's not cheap, but there's nothing better. It'll even let you overcharge now (with the latest firmware) if you think 8.44v is necessary. And they're about to release an update to the PC software that will allow you to control the charger from your laptop, along with watching all the pretty graphs about the state of your battery.
If you don't need the dual charging capabilities of the DUO3, you can get its less expensive single charger cousin the NET3.