Google and Salesforce announced a new product today joining two of the best web-based tools into one suite. Check out this video for an overview of Salesforce + Google Apps, http://www.google.com/a/help/intl/en/admins/video/salesforce_video.html
At my former non-profit, I loved that Salesforce did not require an infrastructure to support. I kept eyeing my problem-prone Exchange server thinking, "Now if I can only get rid of you." Google Apps was a possibility but the migration was daunting and it didn’t integrate with Salesforce as Outlook does. With the added value of integration, the payoff for migration becomes that much greater. Especially when you take into account that both Google and Salesforce offer product donations to 501c3 non-profits.
Any startup or grassroots org without legacy systems shouldn’t even think twice about a platform like this. No equipment. Low cost implementation. Free licenses.