Check the cable near the positive jump start post under the hood. This goes down to the starter, and it is somewhat common for these to get corroded and fail. This cable failed in my car, and I could not jump start it but the battery was good, and all the lights would still come on. If i tried to start it, I would just get a single click, but the engine wouldn't even try to turn over. Here's my brief writeup of my problem and solution:
http://www.1addicts.com/forums/showthread.php?t=1485975