Best Home Theater Amp

Yes, this is an incomplete question! It's like asking, "what is the best car part?", or "what is the best ingredient in a recipie". It's all dependent on the rest of the team, and personal preference, even system matching.
One "perfect" amp for one system might not be even a workable choice for another.

I have found a Sim Audio Titan amp to compete with the best of them for home theatre. It compares pretty favorabley with their W5 model. I used one in an Sim Audio setup. Very neutral sound with 200W/8 ohms and 400W/4 ohms. Plenty of power but a beast with the 5 channel model at over 100 lbs. Make sure you have the room for it

I have only heard Piega speakers but owned Aerials - if you get the Aerials be sure to get a good high powered amp.
In the last two years I have moved from 2 channel to 5 channel (mainly for music, but I also use it for HT) and currently enjoy the Cary Cinema 5 amp. Before that I had the McIntosh MA6900 and before that the Rowland Concentra, both highly regarded integrateds. The Cary impresses me daily - I thought it would be a compromise but it has not been. Plus 200 w/ch - while I have relatively efficient speakers (90 dB/W claimed) it has never flinched, even when driving all 5 identical speakers. I think if I was buying Aerial though (depending on the model) I'd consider 2 of the amps, though that would really create quite a large cable budget!
One bit of advice going off topic - if I was considering any speaker line to go MCh, I'd get their smaller speakers (monitors or small floorstanders) and get a great sub. The bigger the speakers the harder they are to integrate into your room with a 5-7 channel set up, and the sub allows you to adapt the bottom end to the room while the high quality speakers handle the other frequencies well.