Hi dancastagna,
I've got an all Thiel HT setup with very similar speakers to yours (MCS1 center, 2.7s fronts, PCS surrounds, Powerplanes rears, and 4x Higherplanes up top) except for a Martin Logan Descent sub. It had a much more modest beginning with an Anthem AVM20 powered by their MCA50s: 180watts all channel driven at 8ohms, up to 265watts at 4ohms. The amps were, IMHO, just adequate to drive the previous 2.4s and then the 2.7s. I have since added Bryston 28-SST2s to power them and it was a world of difference. The soundstage improved significantly, which I would attribute to improved upper-range bass response. It just filled out the image better. The MCA50s have been relegated to center channel and surround duties, which I think are perfectly fine (except maybe the center but I wasn't about to spend thousands of dollars on a matching Bryston just to power a channel I use less than 30-40% of the time. Maybe someday...). Sonically, I like the Anthem and chances are if I upgrade, I may get the AVM60 even though it's no longer manufactured in Canada--they're crafted in Vietnam now. FWIW, everyone who comes to watch a movie at my house are simply amazed at the sound.
As for the sub, the Descent is perfectly capable of movie duties, but I find it better suited to music since the bass it produces is nice and fast. I've read that there are a few other unique subs that would simply leave others in blockbuster rubble, such as Seaton SubMersive F2, PowerSoundAudio T18HT, and Funk Audio 18.3 (haven't auditioned any of these in person). But alas, I don't have a budget for both a high end 2-channel system AND a dedicated high end home theater. Ironically enough, ever since I got the Brystons and opened up the Thiel 2.7s, I've been listening a lot more to 2-channel sound.
Regarding your question on 2 subs vs. 1, the issue of standing waves is much more prevalent with having a single sub. Depending on your room, it can be a big issue or a small one. Having 2 subs can really reduce that problem and give you more consistent sounding bass.
Let us know what you end up doing with your system.
I've got an all Thiel HT setup with very similar speakers to yours (MCS1 center, 2.7s fronts, PCS surrounds, Powerplanes rears, and 4x Higherplanes up top) except for a Martin Logan Descent sub. It had a much more modest beginning with an Anthem AVM20 powered by their MCA50s: 180watts all channel driven at 8ohms, up to 265watts at 4ohms. The amps were, IMHO, just adequate to drive the previous 2.4s and then the 2.7s. I have since added Bryston 28-SST2s to power them and it was a world of difference. The soundstage improved significantly, which I would attribute to improved upper-range bass response. It just filled out the image better. The MCA50s have been relegated to center channel and surround duties, which I think are perfectly fine (except maybe the center but I wasn't about to spend thousands of dollars on a matching Bryston just to power a channel I use less than 30-40% of the time. Maybe someday...). Sonically, I like the Anthem and chances are if I upgrade, I may get the AVM60 even though it's no longer manufactured in Canada--they're crafted in Vietnam now. FWIW, everyone who comes to watch a movie at my house are simply amazed at the sound.
As for the sub, the Descent is perfectly capable of movie duties, but I find it better suited to music since the bass it produces is nice and fast. I've read that there are a few other unique subs that would simply leave others in blockbuster rubble, such as Seaton SubMersive F2, PowerSoundAudio T18HT, and Funk Audio 18.3 (haven't auditioned any of these in person). But alas, I don't have a budget for both a high end 2-channel system AND a dedicated high end home theater. Ironically enough, ever since I got the Brystons and opened up the Thiel 2.7s, I've been listening a lot more to 2-channel sound.
Regarding your question on 2 subs vs. 1, the issue of standing waves is much more prevalent with having a single sub. Depending on your room, it can be a big issue or a small one. Having 2 subs can really reduce that problem and give you more consistent sounding bass.
Let us know what you end up doing with your system.