Speaker comes on automatically when I call..

solution

For me - it was because on my DroidX I had installed an app called Sanity.

This app, by default turns on all of its "Handsfree" options - one of which will activate the Speaker whenever you make or receive a call.

To disable, goto the application's settings menu under Handsfree and check make sure the box next to Enable on call start is not checked. (I actually unchecked all boxes under this category).