Buzz Aldrin is my favorite astronaut 
Yeah, Buzz is a great one, but I have to say Harrison "Jack" Schmitt is mine. The only scientist we've sent beyond low earth orbit!
I have two -- Buzz, and Alan Shepard. Due to uncertainty over craft reliability, the last chimp to space replaced Shepard, otherwise he'd have gone up before Gagarin. Besides being the first American in space, by dumb luck (Meniere's Syndrome, okay, not exactly good luck) he got bumped from Apollo 14 to Apollo 13, thus was able to land on the Moon. During the 14 mission, docking of the command module with the lunar module didn't go smoothly, and he said, if there's a problem, I'll suit up and dock them together by hand. Mission Control made them undock and redock, to make sure there were no more serious problems.
Later, during the descent to the Moon, radar altimetry failed; after cycling a few times, it started working, but the belief has been that he wasn't going to get within a few measly thousands of feet and *not land*. Shepard did his manual landing, closer to the intended point than any other Apollo mission. AFAIK, Shepard never gave an affirmative comment about whether he would have let the malfunctioning radar stop him.
Shepard also most famously hit a golf ball on the Moon. In the aftermath of watching the ball seem to drift endlessly (it travelled about 50 feet) he managed to forget some film canisters there on the surface -- bringing those back someday will really confound the "Moon landing hoax" nitwiits.
His 14 crew called him "Fearless Leader"; by his own report, after he descended the ladder to the lunar surface for the first time, and looked up at the Earth in the black sky, the Fearless Leader stood and wept.