Contact Remover Plus This app is great for deleting unwanted contact across your accounts (gmail, local phone contacts and SIM card if you have one).
Google Contact Formatter Great for cleaning up your contacts! This app will go through and check all your contacts (Facebook, gmail, Exchange, etc) and update and merge all of the information into your gmail contacts (if you want it to).
Txtract MMS & SMS Backup Backup your pictures and important text messages before wiping you device or archive them off for safekeeping!
Root Explorer (File Manager) Trying to find that one file you know is on your device? This app is great for any type of file browsing and deleting items.
ROM Manager (Premium) Great for partitioning your SD card and fixing permissions of apps when you restore them to a different ROM. Will also help you download and install a different ROM. Backup and restore you current ROM just in case you need to roll back. A must!
*must be rooted!!