I've been using Sonos for audio in our homes for over 10 years. Way easier than using any zones off of a receiver used in a media or living room. I'm a very frugal person, but I do like ease of use and decent sound.
Rundown of our simple setup:
2 dedicated equipment closets - one on each side of the house; one houses most the theater stuff and the other is mostly the audio stuff for the house
~10 zones using mostly connects and a couple of connect amps
Amps for the connects - I use old receivers with analog multichannel inputs. 6.1/7.1 AV receivers can power 3 zones (fronts, surrounds, center/surround back). Just plug the RCA cables from the connects to the desired multichannel inputs, and then connect your zone speakers to the corresponding speaker outputs. Set the receiver to the multichannel input and set the max volume you want (this is good if you have kids that could blow speakers). I install volume knobs in each room (fixed), but you don't have to do this if you want to control volume from Sonos (variable). I leave the amps on all the time. I have amps that have been running over 10 years with zero issues. Most were either old receivers I quit using or receivers folks gave to me.
Speakers - I typically use Monoprice in-wall/in-ceiling speakers. Cheap and decent quality. For areas like over a sink or in a shower, I occasionally use a stereo speaker (L/R in one speaker).
Sources - great thing about sonos is you can plug additional sources into any connect and all other zones can see it. All the satellite receivers have their analog hookups plugged into a connect so you can throw their audio anywhere. For my music library, I have a Plex media server which works with Sonos just like any streaming service. Sonos can also see your iTunes playlists with a little directory configuration. If your living room/media room is a separate 5.1 or greater system, you will need a connect for it to be part of the system. Could also do a sonos soundbar/wireless speaker system to achieve this or even try out the new Ikea/sonos speakers for surrounds.
Alexa - Alexa control is great, but there are some limits. You can only assign one streaming service and she can't play from your local library. So if you tell her to play an artist, it will be from Amazon music, and if you tell her to play a station, it will be from your assigned music service. I just use the app or PC controller to play from my local library. You'll also need to name your zones so that Alexa can easily understand you, and she will only stream Amazon music on one zone unless you set up some sharing stuff. I just use the sonos app for streaming separate stuff to different zones. One cool feature is that when somebody says Alexa in the house, it lowers the sonos volume for a moment so she can hear a command.
Costs - most my amps were free or throwaways, and I bought all my connects used on eBay ($150-200 each). Many of my connects have been running for >10 years. I did all the wiring myself (it's just speaker wire).
Amazon now has a product out (echo link) that is similar to sonos connects, but there are some serious limitations from what I've read. It can't share audio inputs to other links (zones); it's just a local passthrough, the volume lowering with command feature that I mentioned doesn't exist, and you can't set volume to fixed; just variable.
