How to get the "check" next to text messages without being notified?
John as @thunsaker states this a HTC Sense mod and unfortunately cannot be changed.

You could look at rooting your phone and putting a vanilla ROM of Android on or the fully customisable Cynogen Mod 7, that way you can take back the control HTC stole ;-).

A place to start would be http://www.android.modaco.com