YEs, ESPECIALLY FOR A RECEIVER BASED SYSTEM, you really won't get any better POTENTIAL PERFORMANCE (all depends on how well you can set em up in a given room and dial em in) than POWERED speakers like the NHT VT3's for HT/music! They are superb all around, and will dynamically DESTROY most traditional monitors out there for HT playback and overall dynamics! The Built in powered woofers are a real advantage over standard full range passive speakers overall, and just have more GUTS to the sound. Yes, you can, if set up properly, get the same excellent results from a standard sub/sat system, with active subwoofer(s), but it's usually more difficult for people to do as well. When DEF TECH came along and started pushing the POWERED speakers, this really made some good strides for the HT market especially. And, given that alot of people are using the relatively weak and underfpowered receivers to drive HT systems, this kind of approach is a MAJOR advantage in overall performance from a bass/dyanmics stand point. Stereo bass also has it's advantages, and the dual 500 watt carver amps in those 4 10" woofers should have some great potential in modest domestic rooms. The overall sound from the NHT's should be about as good as you can expect if you do things right. And it will make your receiver sound like it's REALLY REALLY strong sounding run full range! Also, the speakers are pretty clear, neutral, and refined sounding through out.
I used to own the Similarly rated Infinity MTS prelude speakers with powered 800 watt subs, and they were also dynamite for HT and music dubties! These kinds of speakers offer generally more potenital for people than your traditional audiophile speakers for doing a 5.1 set up. Get all matching speakers, set em up well, and you'll be rewarded with great sound!
I guess what I"m saying is I think there's NO WAY you'd be dissapointed with the speakers, unless you just did a horriific job of placing the speakers and just SUCKED IT ALL UP that way! Which, may I ad is ALL TOO COMMON among inexperienced audio enthusiests, and the UNINFORMED in regards to setting up systems properly. If you spend time with each speaker, and different listening possitions, pay attention to acoustics and such, you should get good reslults, from otherwise EXCELLENT SPEAKERS! If you have a rather LARGE room to put em in, you'll also have an easier time getting good sound from them as well.