Droid SMS
Those of you with Android (and particularly Moto Droid) should really check out Handcent SMS. Since Android lets any app hook system events (like sms receive) you can simple turn off notifications in the built-in SMS app and use Handcent instead.
There are several very nice improvements over the default:
- Skins. You can use an iPhone skin to get that iChat sms feel.
- Popup notification. If you choose, you can have an iPhone like popup when you get an SMS. However, unlike the iPhone, the popup window lets you do a quick response back without even opening the SMS app.
- Voice to Text!!!! This is awesome. Jsut hit Menu -> Voice when in an sms thread and the standard Google Voice box pops up, just speak your message and bam, the text is put in a message for you. This is killer because its way faster than using and on-screen or physical keyboard. And when you are driving, much safer 
- Widget that launches SMS on click, and displays unread msg number.
All this and the app is free!