51 years ago, I climbed Half Dome. And I did it in one day -- 16 miles round trip from Yosemite Valley. Why in one day? Well back in 1957, concessionaire employees only got one day off a week!
The friend who went with me took one look at the cables you have to climb to get to the top, and decided he had gone as far as he was going to go. So, off I went to the "summit" along with a few other people making the journey that day.
There is a large flat area on the top, and I suppose there were all of six or seven other folks up there when I arrived. Today, you have to stand in line just to get on the cables, and there are dozens of people on the summit at any one time. (For a current views of the top of Half Dome, check Google Earth.)
As an aside, I made the hike in Hush Puppy shoes, and as you might imagine, I had a spectacular set of blisters at the end of the day. Of course, it didn't help that I soaked my feet in the Merced River to cool them off on the way back to the Valley. Back then, there were few "hiking" boots available, and they were very very expensive.
To the left is a photograph of Cloud's Rest taken from Quarter Dome which is on the approach to Half Dome.
This photograph was taken from either Half Dome, or more likely Glacier Point (I can't seem to figure out which), but gives you a good idea of "the view" from the top.