My advice is to download the Decibel X-pro audio app for your smartphone So you can get a rough idea of how loud you like to listen. This will make a big difference. I used to think that high power was required then I got speakers that were 93dB efficient And started listening to 7 and a 1/2 W. And I loved the sound then I went down to one and a 1/2 W and love it even more. But I’m listening right around 70 to 75DB and fairly close to my speakers. This wouldn’t work for a lot of people.
By the way, I think you're getting a lot of good advice on this thread actually. Ultimately you gotta think of things in terms of a system. And the speakers in the room and the amount of stuff you have in the room is part of that system. Donnie Darko (?) has a good YouTube video about room treatment that's worth checking out.