Now that AT&T has announced its new tiered data plans this week (effective Monday, June 7), a lot of subscribers are wondering how the changes will affect them. So let’s take a closer look.

Here are the new plans again:

• DataPlus: $15/200MB monthly. ($15 for another 200MB)
• DataPro: $25/2GB monthly. ($10 for extra 1 GB)
• Tethering: Additional $20/month for DataPro users

As it is, existing smartphone owners can keep their unlimited plans, even if they upgrade to a different smartphone (like, say, the new iPhone, for example). But — and this is important — in some cases, the deal may require a system override. This may happen if a customer wants to jump from one platform to another, like an iPhone 3GS to a BlackBerry 9700. So if you’re a Big Blue subscriber and you have any issues, make sure to talk to a representative. And if s/he has trouble, definitely ask for a manager.

If you’re an existing smartphone customer, perhaps the biggest thing to note about these plans is that — if you have an unlimited plan — you can’t switch to the DataPlus or DataPro, and then revert back. Once you give up that unlimited plan, it’s gone for good. So definitely choose wisely.

So is it worth it to switch? Well, here’s a quick snapshot of where most of these subscribers are with their usage:

• 73% of 11,000 respondents surveyed use less than 2 GB 
• 27% reported data usage exceeding 2 GB

(Source: Wired.com, in a poll conducted last Wednesday)

Even for iPhone customers, some of whose data hogging behaviors have been blamed for incurring these new changes, Consumer Reports found that the average user reaches 273 MB of data per month. And only 4 percent consume an average of 1 GB per month. So even for many of these subscribers, the plans should cover them fairly well.

I’ll be honest — I’m a little surprised by these statistics. Then again, maybe I just happen to know a lot of power users. Whatever the case, it’s pretty clear that DataPlus won’t cut it for most people. That leaves the DataPro as the obvious choice. And for now, it seems the new structure could actually be good news for a lot of users. Sure, it would’ve been nice to have a mid-tier option somewhere between a paltry 200MB and 2GB, but at least these offer some savings, and the upper limit here is pretty adequate — at least for the time being.

And that’s the key aspect of this: It’s fine for now. But in the future, even that top-tier plan may cost us all more in the end. I say “all,” because if AT&T’s experiment succeeds, it will probably only be a matter of time before the other carriers start playing around with their data plans. (So even if you’re not an AT&T customer, you may want to keep an eye on how things shake out here.)

Frankly, I think changes to our collective usage may be on the way that could make these tiers a real burden for users in the not-too-distant future.

There are the hardware improvements that are just begging for bigger, more robust apps to take advantage of them. Bigger, higher res screens and faster processors — capable of enhancing stuff like multiplayer mobile gaming and seamless video streaming — not to mention more powerful OS updates, are already trending high. People will be downloading bigger, more robust apps that take advantage of them. Cloud-based computing is still in its nascent stages, but will grow as time moves on. All of this will take bandwidth.

There are few today who could underestimate the power of mobile platforms, but the key aspect of it has to do with anytime, anywhere connection — otherwise we’d all just use our laptops, tablets and netbooks wherever we can get a wifi signal. Smartphones are supposed to be easier, more convenient and accessible. Restricting that almost seems like restricting their promise.

So here’s my concern: We’ll all probably need more data bandwidth ever tomorrow — but we’ll be stuck with today’s data limits. I’m not talking about 5 years or longer, but within a year or slightly more. So if you’re an AT&T customer, think long and hard before making the switch. And if you’re not, keep your eye on the situation. Down the road, it could affect you too.

Are you ticked, thrilled or fearful of what these plans might hold? If you’re an AT&T customer, let us know in the comments if you’re signing up for one of these data plans — or holding off (and why).