The only reason I didn't jump on the Nexus One was because having brought the HTC Hero I promised myself I'd make the phone last. I was getting a little tired of the upgrade treadmill (not to mention how bad it is for the environment).
However my experiences waiting for HTC's eventual massively delayed release of Android 2.1 along with the pain of finding a Windows machine to force the upgrade (the horror, the horror) have convinced me that for my next phone openness will be much higher up the feature list.
While I still don't demand the same degree of openness on my phone as I do on my PCs I'm relearning the lessons of what it means when you give up the ability to update your core platform.