Play notification alert sound when a message is still open I recently switched to an Evo from an old flip phone.  My only problem so far has been this:

When I finish sending a message, I'm used to just sending a message and putting my phone down.  I don't lock the phone or exit the messaging application.  As a result, if I receive a reply from that person before the phone automatically locks itself, it will not play the text received notification.  This has caused me to miss a few texts completely and is rather irritating.  Is there any way that I can set the messaging app to play the notification sound even when it's for a conversation that's currently on the screen?
Have you tried using an alternative SMS app?  Handcent is very popular.  It has always notified me of a new SMS even with the message still open.

Edit: If you don't want to switch SMS apps, you can also use SMS Popup.