http://www.rchelicopterfun.com/rc-lipo-batteries.html
Times are a changing...
Most LiPo experts now feel however you can safely charge at a 2C or even 3C rate on quality packs that have a discharge rating of at least 20C or more safely, with little effect on the overall life expectancy of the pack as long as you have a good charger with a good balancing system. There are more and more LiPo packs showing up stating 2C and 3C charge rates, with even a couple manufactures indicating 5C rates. The day of the 10 minute charge is not far off (assuming you have a high power charger and power source capable of delivering that many watts and amps).
Once again, the three main things that shorten LiPo battery life are HEAT, OVER-DISCHARGING, & INADEQUATE BALANCING.
I put some good money into a charger and power supply just for this reason. I'm gonna put that bad boy to use at it's full potential. To each there own.
I don't have time or enough batteries to sit around and wait for them to charge in an hour or more while at the track.