Computer Architecture (3rd Ed.) by Hennessy and Patterson (new, $15)

Computer Architecture: A Quantitative Approach (3rd Edition) by John L. Hennessy and David A. Patterson

http://www.amazon.com/Computer-Architecture-Quantitative-Approach-3rd/dp/1558607242/ref=sr_1_1?s=books&ie=UTF8&qid=1343346159&sr=1-1&keywords=9781558607248

New book. Price: $15