A big +1 for 1dollarscan.com. They've scanned many hundreds of books for me. The quality of the resulting PDFs is uniformly excellent, their turnaround time is fast, and their prices are cheap ($1 per 100 pages).
I've visited their office -- located in an inexpensive industrial district of San Jose -- on multiple occasions. They have a convenient process for receiving books in person.
I believe the owners are Japanese and the operation reminds me of the businesses I visited in Tokyo: quiet, neat, and über-efficient.