I do use Expedia occasionally but I like the Travelocity site better. On Travelocity you can scan for the best rate at any time so you don't end up making the mistake of leaving a day later and having it cost you an extra $100 per ticket. Knowing what the cheapest fare is makes it a lot easier to make inexpensive plans. I also think Travelocity makes it easier to make minor changes to your schedule (such as using a different airport) when scanning for the best price. Another thing is that if you use Hotwire or Priceline I don't think you are eligible for frequent flyer mileage.