I've always found that if I know and book ahead of time I can get a massive deal on hotels simply by calling the front desk. It's usually 10-30% cheaper than booking with any service online. I'm not sure why this is the case but if there's a service that can get me front desk rates, I'd be more than happy to switch.
Hell, even if the direct hotel booking is a little more expensive, I still go that route. I've been burned by hotels referring me to Expedia when problems arose. They can't do that when you're direct booked. I still use the travels sites for shopping purposes, then visit the hotel's site directly when I've made a decision.
