I'm interning at a 25 person non-profit. They were putting thousands into Exchange. I did 4 things:
1. Switched them over to Google Apps for free. Saved them loads of money, and they all love having the ease of access. To the exchange admin below, suck it. Seriously, that one outage was nowhere near as bad as the spam problems and other hassles an offsite exchange server created.
2. Got the people who "just couldn't" use gmail's web interface copies of Outlook 2007 through techsoup. Which, after 3 months of switching, was only the secretary and the president.
3. Switched our 5-computer lab for visitors and program members over to linuxmint. It needs no configuration, let alone administration, and its better than the prior windows 2000 by far.
4. Set up Hamachi for remote file access, because nobody used the VPN anyways (cause "my home computer is so slow and full of WeatherBug!").
5. Set up an open source phone server. It was a PITA, but it was WAY better than renting terrible equipment from the phone company.