I'll shower once, maybe twice a day, about 5 or 10 minutes each. Sometimes thrice. My boyfriend rarely takes showers, but takes a bath usually once but maybe twice a week. I kid you not. He just doesn't sweat, or doesn't carry the microbes that cause body odor.
Showering too often removes the microbes that help us produce Vitamin D. But, as it turns out, people now-days rarely get enough sunshine to produce enough Vitamin D, so they're recommending 1-2000 IUs of D supplements a day. One of the things it helps with is reducing susceptibility to respiratory disease, so it becomes important in the age of H1N1.
To take a quick shower, I follow a set routine. I wash and rinse my hair, unless I decide to use a shower cap. I wet my body down, turn off the water, wash my arms, neck, chest, and back; pay extra attention to the pits, crotch, and crack; wash my legs and feet. Turn the water back on, adjust the temp, turn the spray on, wash my face and ears, rinse myself, and I'm done. With a longer shower, I leave the water on, but still stay conscious of getting stuff washed. A luxurious shower, well, I get washed, but take time to enjoy the flowing water as well.