Instantshot! by Digital Waters Projects is a screen capturing software package that claims to simplify taking screen captures. Now i’m not too sure how much simpler it can get than Grab, or CMD+Shift+3, but I’m always up for trying new applications.
“InstantShot! offers classical screenshot functionality for capturing the whole screen, a portion of it or a window and also the option to make timed screenshots or to make delayed captures over time. It offers a wide range of preferences and options to fit everyone’s needs.”
It essentially does what every other screen capturing software does, and for me, it doesn’t do anything that would warrent me jumping from Grab. But, if you really really really hate using grab, you should probably check it out