How much power/channel for multi-channel amp?

First of all, thank you for reading my post. I have a fairly good Denon AVR 2802, which will be used as pre-amp. As for the surrounding speakers, I love those AR Phantom speakers. The handling power is from 50-250 watt with frequency response from 40Hz-20KHz. I am currently interested in a multi-channel amp. What is the handling power per channel do I need for a normal reasonable movie listening and viewing? Is 80 wpc a good recommendation? Is 100 wpc the standard? Is 200wpc the ideal? I like to take a poll to see what amp power do you have, and if it is more than what you need. My idealistic goal is to spend the money efficiently, i.e. to spend enough money for the power that I need -- not more not less but just right. Apparently, I won't blast the speakers even though they can handle it up to 250w. Besides, the I won't have enough money to acquire a 200wpc channel multichannel amp to test my speakers. Any comment will be truly appreciated.
I think you also need to state the room size the home theater is in as well as the speakers' sensitivity and impedence. However, I can't see how anyone can go wrong with an Aragon or a Bryston.
...there is an H/K Signature 2.1 w/100 watts/ch. going for $500 right now - that's only a buck per watt for a pretty nice high-current amp. I'm using one right now and it really does the job for me. It's running Paradigm 80s and a CC-350 in front with Inifinty Silvers for the rears. The room is approx. 20'x15'x8' and it fills it quite satisfactorily.
Thank you for the response. The room size is 12'x13'. The correct response freq is 45-20khz +/- 3db. Sensitivity is 89 db. How important is sensitivity b/c I've never pay attention to it until now? My current HT set up is 5.1. Thank you all for your valuable inputs.
Funny, but I have a 2.1 also and really like it. $499.
You need to consider your room size and efficiency.
Keep this in mind:
86db, 1 watt
89db, 2 watts
92db, 4 watts
95db, 8 watts
98db, 16 watts
101db, 32 watts
104db, 64 watts
107db, 128 watts
110db, 256 watts THX levels
This is for an 86db efficiency speaker. If yours are different, do the math.
You need to double the wattage to increase volume by 3db
To double perceived volume, you need to increase 10db
Depends on how big your room is buddy.

my theater is in an L shaped room, 11ft wide where the fronts are, and it stretches back 26 feet to the rear wall and jolts to the right for the lower half of the L.

im using a Denon AVR-3803, 110wpc and i cant see any reason to put more power into it. Not for what it would cost anyways. It gets louder than any theater i have been to.

I think 100 watts per channel should be sufficient. If you like to crank some music on your HT maybe get 200WPC for the FL and FR channels...

the difference between 100 and 200 watts is what, 3 decibles?
I can tell you that going from 100wpc to a 250wpc higher current design with my 88db speakers in a 14 x 24 room has turned out to be an improvement, but this was mostly due to the higher quality of the bigger amp.
I would go with a minimum of 100wpc and buy the amp with the best sound that you can afford.