Mattlock,
You're receiving some very good advice here, but as an Axiom owner I'd like to make a couple of points. With a room that size, the smallest Axiom I'd go with would be the M22tis.
Axiom speakers can be roughly lumped into 2 groups. The M3s, M40s, M50s are one group, and the M2s, M22s, M60s, and M80s are the other. The M3s, M40s, and M50s have a slight boost in the upper bass/lower area, which gives them a slightly more laid back sound than the other group. The M3s are usually recommended as stand alone speakers (no subwoofer) for a bedroom, or other small room application. All the bookshelf Axioms (M2s, M3s, M22s) really require a subwoofer for optimum results.
The other series, is generally considered a more accurate, flatter responsed, detailed line of speakers (I started with the M22s, but now have the M60s). The M22s with your JBL sub, would get you off on the right foot.
Should you decide to go with Axioms, when it comes time to add the surrounds, I suggest you seriously take a look at the Axiom QS series surrounds. These are wonderful surround speakers which provide an amazingly immersing surround experience without calling attention to themselves. Of all my Axiom speakers, I feel my QS8s do the job they were designed to do the best.
Either of the Axiom centers will suffice.
Once you have all the speakers, I would suggest investigating a new sub (SVS, HSU, Outlaw, Rocket). I had a JBL PB10 before my current HSU STF-2. The HSU is much mo' betta' !
Lastly, if you are seriously interested in Axioms, I recommend you come over to the Axiom forum, peruse some of the threads, and ask any questions you may have. We'll be glad to help in any way that we can. Of course, most, but not all, of us are Axiom owners, and that fact should be kept in mind. But our primary goal is help folks end up with something with which they are happy.
Best of luck. Take your time, do your homework, hang in there, and enjoy the journey