It's an interesting sound, it's just overused recently. There's basically two ways to use Auto-Tune: the intended way, cleaning up the pitch of vocals; and as a deliberate distortion effect, a la T-Pain / Kanye's recent songs. The latter produces a very distinct sound that gets old, fast.
Thing is, people say it gets old because they think that all voices filtered through Auto-Tune sound the same, but that's not true. Kanye's voice through Auto-Tune sounds a lot different than T-Pain's, and you have to be talented to make it sound good. Can it be a cheesy effect? Absolutely. But if tuned correctly, can really add a cold, robotic color to a track.
Personally, I love it. Kanye uses differently than T-Pain and they are very distinct styles I enjoy.
It's a damn fun thing to play around with, too. :P