I have the following devices:
Personal Laptop running Windows 7/Ubuntu 11.10 (mostly use Ubuntu)
Media Server running Windows 7 with PS3 Media Server and iTunes
Work Laptop running OSX Snow Leopard
iPad
iPhone 4S
The iPhone just replaced my Droid 2 Global. What I had been doing was using Google Music to watch the folders iTunes was storing music in and moving any new files up to Google Music. The Droid would pull music down from the cloud via streaming or me telling it to make it available offline, I had folders set up with PS3 Media Server to stream them to TV's via DLNA, and used RDP to play music through my speakers in the office. So far it's worked well.
Since I've replaced the Droid 2 though with an iPhone, I've lost the syncing ability with Google Music and have to do it via iTunes (I knew this would happen, no big suprise). I got to thinking though - Apple does offer iTunes Match, which allows your devices to stream/download the music from 'the cloud,' much like Google Music. I could then listen to whatever I Wanted (for the most part) on my phone, iPad, and laptops by syncing via iTunes Match.
I don't want to loose my MP3s though, and since I've never used iTunes Match, I wonder if the following is a viable solution:
Sign up for iTunes Match on my media server
Let it scan my library and make available my songs in AAC in the cloud
Not delete the media server MP3s
Set up other devices to sync to iTunes Match
Continue to get MP3s via Amazon or other services and add to iTunes
Let the MP3s sync to Google Music, and let the MP3's add to the AAC versions on my devices
I think the main kicker is I don't want to lose the MP3 versions of my songs as those will work just fine on all my devices and I generally rip at 320kbps. I don't mind spending $25/year if it means that I can easily shift the music from device to device without much thinking, but I'm not going to pay $25/year to end up converting my library over to AAC just to save myself the hassle of manually syncing my iPad and iPhone.