TravelPony

I read about TravelPony on a Lifehacker blog written by a travel expert that said that TravelPony found cheaper hotel rooms more often than Hotels.com, Expedia, etc., so when my wife and I needed to book a hotel last week, we tried TravelPony. The site is well-organized and easy to use, and while it doesn't always find the absolute cheapest option (none of these sites ever do, so it's helpful to cross-reference when booking), booking was a breeze and we saved an easy 12% on our room!

TravelPony uses its advertising budget to offer exclusive discounts, which is unique in the booking world, so it's definitely worth checking into!