there are also several apps that can customise the volume, ringtone, etc. These usually also control the vibrate function too.
I use Volume locker, missed reminder and audiomanager to control my phone's various sounds.
Latest update to volume locker is very clever. If I press the volume down hardware button for my ringtone, I get a notification asking whether I want to keep it. If I don't tap the notification in 30s it reverts. Making it a notification rather than a pop up makes it very unobtrusive.