I'd definitely agree about booking.com
They generally seem to have a much deeper inventory than Expedia, including the small local hotels I like. I also appreciate the fact that most of the bookings don't expect me to pay in advance and allow free cancellation.
Often, too, the price I pay through booking.com with those privileges is the same that Expedia offers as a "special" that must be pre-paid!
I would also be less than honest if I didn't mention that TravelGumbo receives a small but welcome commission when travelers book through the link on our site. Since our own experience of many bookings with booking.com has been so positive, I'm happy to recommend them!