In a recently (Oct. 3, 2014) posted blog by Kim Klein, the question of how to greet donors and prospects in letters and emails is addressed. While the article seems to favor erring on the side of formality, when in doubt, it also recognizes that there are times to be informal, and even quite casual, during correspondence.
In FundRaiser the word processing is built into the program, allowing access to all fields of data for merging into letters as needed. This enables you to write "form" letters that have the personal look and feel that used to be possible only through individually crafted letters. The way you greet people in a letter can be personalized for each name record in FundRaiser, as well.