My main road bike has a 10-speed (SRAM Red) drivetrain with a 50/34 crank and 11-28 cassette. I own a standard (53/39) crank, but find that I tend to spin more with the 50/34. My knees like that a whole lot better. My Ultegra-equipped touring bike has a several different setups: I use a 52/39/30 triple crank with a 12-27 cassette when unloaded, but switch to a 48/38/26 trekking crank for credit-card touring or a 44/32/22 mountain bike crank when carrying heavier loads.