Sonos Sound System - what do you think?

I suggest getting an AVR, some quantity of more or less matching minimonitors from thrift stores/pawn shops/craigslist, a used (semi)pro power amplifier (200 to 1200 watts per channel), and building two or more subwoofers with 12" to 15" drivers. See the DIY section at AVSforum.com and google diy subwoofer.

By minimonitors I'm referring to the innumerable small but not tiny speakers with dome tweeter and 4 to 6" midwoofer. PSB Alpha, Paradigm Atom, NHT Zero, Optimus LX5, Minimus 7 (yep, the last two were sold by Radio Shack), or whatever similar quality speakers happen to have been popular on your planet. It's not unusual to pay $10 for a pair in working order. One warning: google foam rot, and learn to spot that disease of old speakers.

Sonos is great. If you are using it for TV, I would suggest buying the Playbar (Sonos' soundbar) and the sub woofer. If you can afford it, you can add two of the "Play 1's" and make a simulated 5.1 home theater system.