I too bought the nice, but economical Hooker 2.5" cat back system, with their Aerochamber muffs. I already had the Hooker headers, which act kind of like longtubes on a V8.
The whole system has a unique, nice, crisp sound. Not loud under cruising speeds, but sounds mean when you stand on the pedal.
It certainly doesn't have the throaty rumble of my previous 3" FlowMasters (bad choice for turbo car), but, the Hooker system performs better, per their angled/straight-flow muffler design.
I personally hate the sound of a single-shot 3". Although it performs well, it's "blatty", and way too loud for cruising.
I've heard great things about the Dynomax Ultra Flows. They're a true race muffler w/ straight thru flow, but have a nice rumble. A little loud, but a good choice.
In the end, you need to determine your personal goals and tolerance for sound. If you don't plan on riding on the highway at 2400 rpms, then any of the systems mentioned are good, however, if you want to avoid the resonating drone, you may want to shy away from some of them. For me, the Hooker system was the best bang for the buck, and met my needs/goals. If I need to run full-out, I just open the electric dump...