That one is good too, though it can get a little obscure in some sections.. I tried reading it twice! The first time I was stuck on the memory chapter. The second time I was stalled by the clock and synchronization thing, but it's still a great book. I hope I can muster the courage to read his Annotated Turing Paper.
Especially chapters about virtual memory and memory hierarchy and the one about processes and traps.. I didn't know anything about these things when I started reading the book.