How do organizations make purchasing decisions?

I was chatting with a neighbor a few days ago and the topic of how organizations actually select technology came up. That's an interesting area, one that my team at IDC often probed using various demand-side research tools. In the end, it is clear that in commercial organizations (as opposed to academic or governmental organizations) often purchase emotionally rather than logically. Have you noticed this? Here are some points that came up during the lively conversation:

• For the most part, purchasing decision makers have already made a choice before they bring in consultants, analysts and other influencers. Their choice was driven by something they read, what a golfing/tennis/insert your own favorite sport here buddy just did or what a recent business jounal said was the hot technology of the decade. These decision makers typically seek out someone that agrees with their pre-made decision and then purchase a report, an executive advisory session or something of the sort. This way, if higher levels of management ask why a certain product or service was acquired, it will appear if a carefully planned process was followed.
• Very few organizations have taken the time to come to grips with what they're currently doing with technology, what their plans are for the future, and then developed a pragmatic architecture that will be the foundation of all future purchases.
• Many companies start with a product and flesh out their ideas from there. I believe it was Abraham Maslow who said "If the only tool you have is a hammer, you tend to see every problem as a nail."

This behavior tends to lead organizations to incorporate the "Golden Rules of IT" into everything they do even if it gets in the way of future growth.

Can you add thoughts to this list?