well your contact info is stored in your gmail account all your music and photos should be on your sd card. so those will be uneffected. your apps i will tell you that when i did it the first time i went to the market I hit menu < downloads and it had a list of all my old apps. I screwed myself by ownloading a few then exiting the screen to clear notifications or something and the next time i went to downloads it only showed the few i had just installed. So just go through the list and re-download them all before you exit the screen. or you can download "my backups" by reware from the market and backup everything home screens wallpaper and all wiget layout basically exactly the way your phone is set up. do this before anything else. the only problem is it does not install market links. this means your phone will have all the apps but the market will not see them so you have to reinstall anyway.
For all that were curious, I fixed my problem. I was just about to do the backup when I just randomly came up with an idea. remove the sd card. Reboot device and turn back on. Some reason the sd card was causing the problem. Its now fixed.