The HT-S3100 is your basic 5.1 home theater system with capacity to hand HDTV via component inputs. Up to three hi-def devices can be displayed on your HDTV, switched automatically. It also has plenty of standard analog inputs for your legacy gear.
The HT-S4100 is the same system, but adds a powered subwoofer to the package instead of the non-powered variety the S3100 has.
The champ, though, is the HT-S5100, which is an entirely different package, and one of the best deals for the price I’ve seen anywhere. It’s a 7.1 surround sound system instead of 5.1, giving you two additional channels of surround audio.
The S5100 also includes three HDMI inputs as well as two component and four digital audio inputs. This is for serious home theater fans.
Other niceties include an integrated iPod dock and Sirius satellite radio connectivity, dual speaker zones, and several legacy inputs. This would perhaps be the last theater system you’d ever need, and at $579, it’s a very good price.
The S3100 and S4100 are $379 and $479 respectively, and great for beginners, but if you’re a serious home theater guy (as I am), you’re already checking your current system to see how it could compare.