Tasker is a must have. You can do so much with it and it makes your phone actually smart.
Greenify is also another good app for saving some battery life
Poweramp
Nova or action launcher
Tasker
If you drive a lot car home ultra
Datavault for passwords, data etc.
Isyncr to sync playlists with itunes
Any File Explorer. I use Root Explorer even though I'm not rooted.