I have to admit I never really liked the idea of "who is the best astronaut?"
My favorites are Jim Lovell, Neil Armstrong, John Young, Steve Lindsey, Robert Crippen. No particular order. It seems that people always like to value the Apollo guys the most. But I have great respect for Shuttle astronauts. Working on things like the HST and ISS, impressive stuff.
When I went down to KSC and saw the Astronaut Hall of Fame, I thought "How odd! I would consider any astronaut that flew into space to be worthy of the Hall of Fame."