Folks, I like Ryan Hall as much as you do. But, the threads proclaiming him the greatest American marathoner of all time have to stop. Yes, Hall is fast, but, he has won only one marathon -- the US trials (yes, his London race was impressive). But, you need to put things in perspective.
It's clear to say that the GOLD standard of American Marathoners is Frank Shorter. Shorter won the Gold, Silver (arguably should have been two golds). He was ranked #1 in the Track & Field News World Rankings 1971, 1972, 1973. Shorter won the 1971 Pan American games marathon in the heat, and won FOUR Fukuoka marathons (1971-74), when that was arguably the best/deepest race in the world.
Aside from marathoning, Shorter won the U.S. national cross-country championships four times (1970-1973). He was the U.S. Olympic Trials Champion in both the 10,000 m and the marathon in both 1972 and 1976. He also won the 10,000m at the Pan-Am games and came in fifth in the 10,000m in the '72 Olympics. He won the 10,000 meters in the USA-USSR dual meet.
I expect great things from Ryan Hall. But he has a LONG way to go before being considered the greatest ever.