I have a 14' x 16' HT room with no back wall, and a $3,000. budget. I can't decide between a good 3.1 or 5.1 system . . . . . viewing is 10' from front 14' wall. - 65" Sony Bravia mounted - w/screen center 48" above the floor.
If wiring surround speakers is not practical for you a 3.1 will work fine. Some special effects will not work as they should but surround sound is not a substitute for good sound. Better quality speakers in the front are what make a system great. Clear dialogue at low volume and correct flat bass really make watching movies more enjoyable. Surround effects are fun with some movies but if you don't have clear dialogue you find yourself raising the volume and then lowering it when the sound gets loud. It is critical to get front speakers that a voiced to match each other. Your budget allows you to go beyond low end audio so if you have a good high end audio shop in your area pay them a visit. They can help you compare speakers and get the best fit for your ear and your budget.
If you've got that much available, why not invest in a high end sound bar/sub setup? There are several excellent quality ones out there now with Definitive Technology being my fave. While a sound bar isn't an ideal setup, it may give you the best solution to your problem.
Be sure to disable the surround/rear channel in your receiver, this will force those signals to be pumped into the front left/right. I recently bought a Mirage Omni Theater sound bar and it's killer. I honestly disconnected by rear speakers because they weren't worth the hassle (wires all over the place) considering the sound I got from the bar.