Michael Tiemann confirms a Forrester report that suggests that freedom, not cost, is what is driving CIOs to open source. This may be true, but my experience is that it's usually cost that first opens the door to open source. It's hard to beat getting something for nothing.
At any rate, "freedom" defined by CIOs is a little different from "freedom" defined by Richard Stallman:
Almost half of all respondents interviewed in the Forrester study cited open standards, a lack of usage restrictions, and not being locked into a single software vendor as their primary reasons for looking at or adopting open source solutions. Lower initial purchase cost was cited as important by most interviewees, but just as important is the ability to customize these packages to specific business uses - especially in vertical markets. And although most noted that they won't really change the code, having that option is very valuable to them.
It's largely the same, but without the political creed. For the CIO, open source matters because it makes software truly software. That is, something that they can shape to their needs. Without a vendor cracking the whip over them.
For those who think source code doesn't matter to end users, take a look at the income statements for Accenture, CSC, SAIC, etc. These companies get paid a lot of money to modify software for end customers. Such modification is easier with open source.
Software freedom matters. It matters for very practical, boring reasons. It matters because it makes software less risky and more efficient.