Don't buy 15-minute or 1-hour chargers!Actually, there are some fast chargers that are good. Its the cheap ones that just pour on the current and badly overheat your battery that are a problem. 10 or 20 or a few more recharges before a battery dies is not uncommon with them. Then users blame the batteries.
As somebody has already posted, you want to charge at ~500ma or thereabouts, no faster.
I'd recommend the MH-C801D charger, and it's a 1 hour charger.