Also check out this film, also available as an iPad app (NASA Ascent), 45 minutes of gorgeous slow motion launch photography from the numerous cameras on and around the pad narrated by two guys who ran the operation.
https://www.youtube.com/watch?v=vFwqZ4qAUkE
One great geeky detail of the SSME start process was that the engine bell vibrated quite markedly as the engine lights up. The flight position of the two lower engines (no. 2 and 3) placed the bells very close together and there was a chance they could collide during the start so they were held apart during light up and then gimballed back into position once they are up and running. Easily visible on close ups of engines during launch.
Another vote for Riding Rockets by Mike Mullane, great behind scenes look at the operation, warts and all. One thing that is very clear from the book is that the astronauts themselves were under no illusions about how dangerous and marginal the vehicle was and the risks they were taking with every launch.