IMO, get the cheapest AVR you can that has a full set of pre-outs to drive a 5 channel power amp. Then you'll never have to worry about power again. Also when the AVR becomes obsolete or breaks in a few years, you won't be out a lot of money. Just replace it with another cheap AVR as the mainstream manufacturers seem to change models every year. There always closeouts or demos, especially in the Fall when the new models come out at discounts at 50% or more off MSRP.
Meanwhile that 5 channel power amp will keep pumping out the watts and be ready for that next AVR. And the next one. And the next...Well you get the idea. Good luck!