A lot of folks are still on those old plans, even though AT&T is upping the price from $30 to $35 in February. The company infamously started throttling the "unlimited" plans after a mere 5GB of data usage, a move that caught the eye of the FCC. The regulator said that AT&T didn't adequately notify users about the drastic speed reductions, and slapped a record $100 million fine on the carrier (AT&T plans to fight it). Several months later, AT&T increased the throttling limit to the aforementioned 22GB, a move it likely hopes will assuage the regulator.

If you sign up with three other users, the fourth line is free, so the whole shebang runs $180, or $45 per user -- though you have to pay the full price of $220 for the first two months. If you call and text a lot, it might actually be worth dropping the grandfathered data plan, though many folks might prefer to cut off an arm. If want to use a tablet on the new plan, it's $40 per month, considerably more than with AT&T's 20GB Mobile Share value.

It was clear that AT&T would capitalize on its purchase of DirecTV after it offered its first 10GB shared data bundle back in August. The new Unlimited plan might tempt away users of T-Mobile's Simple Choice plan -- which offers unlimited data for $95 a month (throttled at 14GB for tethering) -- who also have DirecTV. To figure out whether it's worth your while or not, though, you'll likely have to bust out a spreadsheet, given the complexity of carrier pricing.

[Image credit: AP Photo/Richard Drew]