One of the great things about HTC Sense on the HTC HD2 is that it’s such a heavy redesign of Windows Mobile. Unfortunately, this can cause problems with some other applications. For me, HTC’s text messaging application replacement disabled Microsoft Voice Command’s ability to read my incoming text messages to me over a Bluetooth headset. That’s unacceptable for me, so in order to disable HTC’s Messaging application and get the default Windows Mobile one back, I had to install Zenyee Disable HTC Messaging 1.2.CAB which is available in this thread on XDA. After installing that and rebooting, the native text messaging app is back, AND Voice Command’s ability to read incoming text messages aloud to me has returned!
Incidentally, if you’re looking to remove some of HTC’s other customizations and bring your HD2 back to a standard Windows Phone style operating system, that same thread has a lot of other tips for doing so.