NHT in Home Theater Setup

I don't know how much of a bass fiend you are,
or how big your listening room is, but the bass
of the 3s is pretty incredible for their size.
I have them, and I forget that they're monitors
on stands. Hope this helps.

If you are going to use the standard 80HZ crossover points with a sub, I would go with the Classic 3's. If you don't want to use a sub, go with the 4's.
I use the 4's in front, the 3's as surrounds and the Classic 3 center. Using the 80hz THX crossover really negates any advantage the 4's have. Set up with the 4's crossed over at 40hz, the 3's at 60Hz and the center crossed at 90hz gives a much bigger sound overall. I'm also using an HSU VTF3 HO w/turbo sub. For movie tracks, you really need the sub. For music, I kinda like the 4's without the sub better unless it handles just the lowest of frequencies.
I driving the system with Parasound Halo amps all around.
I'm really a 2 channel guy and this is my first real go at HT. I'm still learning so you may get better answers elsewhere but this has been my experience.
BTW, the NHT's sure are good speakers for the money IMO.

I bought three of the M5 for the HT set up and I am very dissapointed as comparing to the Super Zero I owned some ten years ago. I have nothing but Bright and forwarding and super thin sound from these M5s...I can only use them for the movies with THX EQ on. Two channel listenning is Audio Hell. Despites all the good reviews, the M5 is not what you want if extended high is not your cup of tea.