I have a couple clients who are looking at upgrading their respective SBS servers in the near future. Unfortunately SBS is no longer being sold (separate topic there), so I'm in the need for something that can replace their core business functions.
1) AD - Something that can authenticate users, control work places, etc
2) Exchange - either a hosted solution - office 365?? GAPPS?
3) File sharing - A way to control who can access what. If I had AD I could setup a NAS (Synology?) and that would control who could see what.