For text messages I like to have them vibrate and not have a ringtone. I went in Messaging Settings and checked vibrate. For the ringtone I also checked silent. But every time I recieve a text message the LED light will flash and it will show up in the notification bar, but it won't vibrate. When I check the vibrate and ring option in the sound settings, the phone will vibrate for text messages, but it will also vibrate on calls and I don't want that. I've had this problem some time after I recieved the Ice Cream Sandwich update, I believe.