Wireless (digital 900Mhz) speakers from Cables Unlimited (available at Newegg) are simple and work well enough to satisfy many listeners. I use 4 of them with a server running the Squeezebox Server (free) and the squeezeslave application to get whole house audio.

I've had to deal with a similar situation. The bottom line is that Exchange sucks if you don't use Windows. We have IMAP enabled so email access mostly works. Calendar access is a more difficult issue. It annoyed a few of my colleagues and me enough to write a Java application using EWS to export to iCal for read only access to calendars. We still need to use web access (OWA light) to make calendar changes. Our code is here http://code.google.com/p/exchange-calendar/