Travelocity is now offering their own alternative to Hotwire and Priceline, selling rooms at a discount by not revealing the name of the hotel until after you've made your purchase. It's not exactly new, as they first launched it about a year ago in several major cities, but they have been expanding and refining the program so it is now available is most areas.
The service is more similar to Hotwire, as you are given a price, location, and star level to pick from before you purchase, rather than "bid" as Priceline offers.
The big advantage I've found so far is that Travelocity seems to charge significantly less for for Service Charges. For example, I found both Travelocity and Hotwire offering a hotel in the same area for $29. Taxes and Fees on Travelocity added $4 to the total, Hotwire added $10, and A Priceline bid of $29 added more than $11 in taxes and fees.
The biggest downside I've found is that Travelocity does seem to "overrate" hotels compared to the other service. A few hotels I've booked via Priceline as 1 star hotel, have both been ranked as 2 star by Travelocity. If you are looking for quality, the other services may be a better choice, and I still comparison shop between all three, but when looking for the best possible price, Travelocity's Top Secret is certainly one to check out.