Greetings iwiber,
Titanium will backup your apps and data, but it will do nothing for your phone information.
Your contacts and such can be synched to your gmail account.
I use sms backup manager to save text and sms messages. There are other apps available to back up your sms.
Most of the replacement launchers have a option to save and restore your settings.
Important notes:
1. Do all of you backing up before the factory reset! Lol, I know this is a given, but sometimes people do things without thinking.
2. Most of the backup stuff will default to your S3 internal memory. You will have to move that info to a external SD card before you do the factory reset. The S3 internal memory will get erased.
3. I don't know how comfortable you are with tinkering with your phone, but if you have some patience and are willing to read up on the subject, I would point you into the area of a custom recovery. With this in place, you can do a complete backup of your device. After a factory reset, you could return your phone to the exact point it was when you made the backup.
Again, number 3 is a more advanced thing to do, so if your not comfortable or wary, don't do it.
Samsung Galaxy S3 - Android Forums
Hope this helps.
Welcome to the forum.