[update July 2011] So I finally bit the bullet and clicked the "clear data" button for the Dialer application. It was at an incredible 70MB, but I feared I would lose all kinds of contact information. Turns out it has more to do with stored SMS and MMS, as all my messages were wiped after doing this (luckily I thought to run a data back up before doing this. I guess HTC thinks it needs to
