HTC: Sense vs. Android Stock UI

[johnnycakes2]

Here's a question for anyone who might know:

If you have an HTC Android phone with Sense, and Android comes out with a new version, i.e. 2.5 "Froyo", can you deactivate Sense on the phone and simply upgrade OTA to Froyo, or is it impossible/not allowed/too complicated unless you root your phone?

I'm in the process of getting an Android phone, or maybe I'll just wait for the Supersonic. My biggest fear is that I'll be stuck with a device that has Android 2.1 and Sense until whenever HTC decides to upgrade it, and that, most likely, will be the only official upgrade I ever see.

So can you easily deactivate Sense and go with stock? What happens if you do upgrade OTA and try to reactivate Sense? Anybody have any experience with this?