Handcent SMS

Developer: handcent_admin
Price: Free
Handcent SMS should be the stock option for text messaging.  This app makes text messaging easy, and the amount of settings you can change is astounding.  You can literally change everything about text messaging to your preferred settings, and even have different notification settings for different contacts.  It is impossible for you to fully get the picture without trying it out for yourself, but I can guarantee that once you try out Handcent, you will stick with it.  Bonus features: Text-to-Speech, and Speech-to-Text.  Download this app now if you use text messaging.