It takes me about 10 minutes to clean my bike and I can do it quicker if I have to.

A sparkly clean drivetrain helps reduce wear, especially if you ride in areas with sand on the road (like some areas of CT after a winter of snow). I've worn out an XT chain and cassette (on a mountain bike) in less than two weeks due to riding in muddy races/conditions. My brake pads would be gone after an hour or two in a muddy race. Grit acts as wear accelerators, like wet sanding all your equipment with every pedal stroke. Keeping that stuff off your drivetrain really helps.

The process, 11 minutes including taking pictures.
http://sprinterdellacasa.blogspot.co...ike-quick.html

The tool I use now, the Grunge Brush.
http://sprinterdellacasa.blogspot.co...our-chain.html

I used to wrench in, manage, and own a bike shop, a total of about 15 years in the bike biz. Our tune-ups included cleaning the bike and that meant the drivetrain. For new mechanics (we called ourselves Pit Slaves) the rite of passage involved cleaning really greasy bikes for a few weeks. I've tried all sorts of things. I find that leaving the chain on makes it less likely to make errors; the chain tools that have rotating heads wear out quickly and leak degreaser; cleaning the chain/drivetrain regularly makes it much quicker to clean it at any given time. I wish the Grunge Brush existed at the time.

The Grunge Brush works great, gets multiple sides of the chain, doesn't wear out super quickly, doesn't necessarily leak dirty degreaser all over your hand/arm, easy to use, doesn't get all tangled up in the chain, etc.

It's important to rinse well, whether with a hose or a bunch of bottles. Depending on outside temperature, if I have access to a hose, etc, I'll resort to using waterbottles to rinse off the bike.