I have Norh 9.0s actively bi-amped with active crossovers. This was allowed for by a specific design by the manufacturer.

They originally had passive crossovers in them but had extra posts for active biamping. I had to open them up and rearrange the wiring to 2 posts per driver.

This setup is for my 2-channel listening and I can really hear a difference. But remember each driver is getting its own 100w amp! And the crossover points are set for optimum performance of these particular drivers.

In the near future I will triamp with a 3-way active XO and bring in a set of sub woofers.

I am going to all this trouble and expense for 2-channel, and HT will get some benefit from it. Not sure I would do this if I didn't have high end audio sources, and especially for just DVDs. I am not convinced that the DVDs that we have are of high enough audio quality (compression and all that).

unless you can defeat the internal crossovers in your speakers and use an external crossover, biamping does nothing more than add twice as much power. you can sometimes see more headroom (as it is typically called) by using two amps of equal quality as one that is 2x as powerful though.