m3freak, if you are getting a multi-zone/multi-source amp and putting it in the basement where all your speaker runs terminate and having MDs in each room remember you will need to run line-level cables back to your basement for the MD sound card outputs.
Doing all your MDs like that also limits your sound to stereo - assuming you don't have an in-wall/in-ceiling 5.1 setup.
I was planning on using the ceiling speakers only for music/radio (i.e. whole home). This way I could use multiple sound cards in the core or MD, which would also be in the basement. Basically, one MD could be dedicated to running the audio system. In this scenario, stereo would be fine.
I know this partially goes back to the old way of doing things, but for listening to music/radio in various parts of the house, it should work out well.
As for individual bedrooms, the MDs there will be connected to PC speakers or televisions. I'll most likely have ceiling speakers in the master bedroom (I already have speaker cable run to the master bath). I may use an amp in the bedroom for the bedroom ceiling speakers, but the bathroom speakers are going to be connected to an amp and core or MD in the basement.