A couple of things that I would add: If you want the good deals out of Chicago (like Jetblue for NY) its Airtran from Midway Airport. Did it once, not too luxurious, but cheap cheap cheap!
Also, and I do not think that this can be stressed enough,BE CAREFUL WHO YOU BUY TICKETS FROM! Esepcially for Disney and Universal, there are many stands outside the Disney Grounds offering ultra cheap tickets. Do not buy them! The tickets might be unauthorized and Disney will not accept them! If you want cheaper tickets, pretty much looking through AAA is your best and sometimes only best bet. Outside of Disney, I do believe the Flex ticket for the other Major Theme Parks are still around. The game with Disney is to decide how many days you plan on going and then buy said tickets. Disney reduces the price per day if you buy more.
Many, if not most, of those booths and fronts you see for "discount" tickets require you to sit through timeshare presentations, IME, so my thoughts on them apply.
Went to DC this past June, roundtrip from Seattle on Airtran (hated it) and the tickets were still pretty spendy. Again, I wonder if it has anything to do with the distance?
I've been leery to use priceline.com because it appears you have to pay for your ticket without knowing who you're flying through, how many layovers, and what time. Too many unknowns for me.
Another avenue to pursue if you want to book an ALL Disney trip is one of the authorized Disney planners like Small World Vacations. They do an excellent job of getting you the best out of Disney for your buck. There is no extra charge for their assistance, but you should make sure you are serious about a vacation (and do some of your own research) before using their service.
On a side note: rumors are circulating (www.touringplans.com) that some bargain basement, room-only discounts will be offered at WDW this week. Keep an eye out for them....