Travelocity...

I book every trip online... including our honeymoon. I saved a BUNDLE. ($4k for 10 days in athens, crete, and santorini in june!)

Most major hotel/flight booking sites are fine to use. I highly recommend using tripadvisor.com for booking hotels, since you can choose your hotel by location and reviews, and then use the sight to search 5 different reputable online sites for the cheapest price for the exact hotel you want....

best advice, book well in advance to get the best prices, and the flights/hotels you want!