I agree, you are not going to find better than the Affordable Accuracy for $300/pair!There is an ongoing argument about which is better bookshelf speakers or floorstanders (if it is a given you will use a sub to cover the bass).
However, there isn't (shouldn't be) much argument over which is better if you are on a budget. The typical difference between a bookshelf and tower can buy a lot better sound quality in the budget arena!
20 X 20 is a good sized room and 15' is a pretty good distance (assuming that is also roughly the distance to the speakers). You are going to need speakers that can play pretty loud. The AA's are the best value for overall Sound Quality, however, you might consider Klipsch RP series speakers. The new RP Klipsch do not have the legendary harshness of the older models and I think they are the best value for a budget speaker if max SPL is a concern.
You can get the RP-600m from Corey at 270-556-8427 (Paducah Home Theater) for $350/pr shipped. I think they are technically sold as open box, but the speakers I got from him were new as far as I could tell! He has a warehouse in Kentucky he ships from (he direct ships from Klipsch for the high dollar stuff, but the RP series ship from his own facility).
https://www.facebook.com/PaducahHomeTheater/
Don't get me wrong, the AA's will play loud, and will manage 15' at good room filling levels; however, if you are one of the guys who really likes to crank it from time to time, the Klipsch are comfortable playing loud and happy being powered by a modest AVR.