I'm reading Hackers by Stephen Levy right now and DEC's pdp computer era as described seems like a real golden age. I'd enjoy more history book recommendations along this line if anyone knows of some
Specifically about British computing is Electronic Dreams (Tom Lean) (disclosure: I went to university with the author).
The Cogwheel Brain: Charles Babbage and the Quest to Build the First Computer (Doron Swade) is also an interesting read, especially as Babbage's ideas were eventually vindicated when the Science Museum built it in the 1990s and it worked.