Hi all,
For once I get to chime in with something I can actually help with.
I travel a LOT. Some of the time I get to go through my company's travel office - quite often I have to find my own way and then get re-imbursed. In my time I have found a few very helpful sites for travel and a couple of other things along the way. I have put together quite a bit of info for my teams in the past - here is some of that for you . . .
First - there is no single site where you will always get the best deal. I have, however, found that the two mentioned on the OP are usually two of the highest. I have found Kayak.com, CheapFares.com, and UltimateFares.com usually have the best rates when compared to others. That is not to say they have the best 100% of the time - but usually. Compare first - then buy. Certainly compare to the airline sites - but I have never seen a time when the carrier's site offered better prices than these sites.
Second - good rates are often found in out of the way places. Sometimes airfares to main hubs are high - they are high volume and most are trying to get through them to other places. If you can find flights/legs through smaller, out-of-the-way airports then you can often save some money. Get a copy of the OAG or book mark the site (
http://www.oag.com) - it's helpful and has every scheduled flight in the world. If you know what flights are going where you can usually put that info in the ticketing sites and find some amazing gems. Perhaps it's worth saving a bit if you only have to travel an extra 20 miles (compare flights to Midway vs. O'Hare - then add the extra crowds - just an example).
Third - know your flights - namely where you are sitting. That can make the trip a total nightmare or a be a great start/end to your travels. To find out what kind of seat you have you need to know the kind of airplane (the equipment on the ticket - i.e. MD-80, CRJ-45, L-1011, 747 and so forth - it's on the ticket/itenerary). From there, and the seat assignment you can look it up on
www.seatguru.com and know what amenities are available (such as power outlets???).
The end of all this is - don't limit yourself to just one or two sources. There are several ticketing sites out there for the casual and professional traveler. Look around and become informed.