sound bars. They try artificial means of bounding sound off the corners of symetrical rooms to enhance ambiance. The better sound bars are relatively expensive. With just the front space available, you can work towards as 3.1 system. First step doesn't use a relatively expensive center channel which greatly reduces the relative importance of the front L&R speakers. Get decent front L&R speakers and add a good sub woofer for 2.1. There are lots of lousy sub woofers. Save to get a sub woofer for at least $400-$500.
Check out such sites as HSU, SVS & Outlaw. And go to AVS forum for threads on sub woofers.
Last step is to introduce a center channel. It firmly anchors the dialog close by the screen. It will encompass typically 65% of the total audio sound info. As the most used speaker it is apparent you ought not to skimp on quality for the center channel. It is possible to get good audio balance with different brands of center versus front L&R, I advocate matching brands for more easily attainable sound character between center & front L&R.
Yeah, this way may cost more for speakers in the long run but I believe it is money well spent. Speakers may seem to cost a lot up front but they basically don't just wear out & a good selection will satisfy for many years. They get less obsolete over time than the components.
Invest for the long run & appreciate you have done the right thing. It is for the pleasure of your ears alone, no one else.