Yesterday Helio announced a limited-time offer $99/month Unlimited plan that gives you all the voice, messing, and handset-based data (read: no laptop tethering) you can stand for just under one hundred bucks a month.  Today Sprint - Helio's network provider - chimed in with their own offer: Unlimited "Everything" for $119.99/mo, with laptop tethering available as a $30/mo add-on.  (Note that the offer is currently only available in five US markets.)

For the extreme power user, these plans ain't bad.  $100 to never have to worry about how much you talk and text, and to get Email and Web access everywhere on your Helio Ocean or Mysto is a good deal, and $120 for Sprint's package gets you better customer service and a wider choice of devices, including true smartphones. 

$150/month with the tethering option will appeal to some corporate and small-business types who are always on the go and need voice and laptop-data access wherever they roam.  But it's still a bit pricey for the "average" power user like yours truly.  I'm thinking the magic number is $99.  If I could get all the talk, text, and Web I wanted, on any device I wanted, with full-on 3G data speeds, for one C-Note a month, I'd be seriously tempted.

Right now I pay $50/month for voice and data from T-Mobile, and usually kick in an extra $5-10 each billing cycle for SMS and other overage charges.  Add to that $30 for my half of my shared Cable Modem at work and another $30 or so for another Cable Modem at home, and I'm over $100 monthly.  Granted, I have a family plan with my wife, so to be fair I'd have to work in the cost of a second voice and text package for her. 

I'd also have to work some magic to turn "laptop tethering over 3G" into the equivalent of dedicated Cable Modems at the office and in the house, but you get the idea.  $100/month for Everything makes a lot of sense for the data hungry among us.

I don't think we're all that far from the days of one reasonable monthly fee for voice and data wherever you go, and on whatever devices you choose.  Come 2009, in fact, I expect we'll see cellular broadband really make a push to take some market share from DSL and Cable Modems in the mainstream US market.  Especially if this whole WiMAX thing hurries up and happens, already.

Meantime, if you're in the market for a new voice and data plan, I'd give it another month or so.  With Sprint having already broken the seal, it stands to reason that AT&T and VZW can't be too far off from offering their own $100-ish unlimited monthly plans.

Learn more at SprintUnlimitedAccess from here.