Which iPad should you get, 3G or Wi-Fi?So, you’re giving an iPad 2 to a special (and very lucky) someone for the holidays. But which version should you get for them: the Wi-Fi-only version, or the pricier 3G-plus-Wi-Fi model? And what is the difference between the two, anyway?

Read on for four things to consider before plunking down your cash, starting with…

1. With the cheaper iPad, you’ll need Wi-Fi to go online
Let’s begin with the basics, starting with the fact that the Wi-Fi-only iPad does practically everything the 3G model can, from browsing the web and sending email to streaming video and chatting online—provided your iPad is connected to a Wi-Fi network, that is.

But once you leave your living room—and your home Wi-Fi connection—behind, your iPad won’t be able to connect to the Internet until you find another Wi-Fi network. And while there are plenty of public Wi-Fi networks in airports, hotels, parks, and other public spaces, they’re typically spotty and expensive, not to mention frighteningly insecure.

Of course, you can still use an iPad even without the Internet; for instance, you can still tap out notes, play music and videos stored in the iPad’s memory, or play games like Angry Birds. Just don’t count on any web surfing, music streaming, or triple-word scores in the online-only Words With Friends.

2. A 3G iPad means freedom from Wi-Fi (for the most part)
The 3G-enabled iPad, on the other hand, can connect to the Internet pretty much anywhere there’s cellular service—and when you’re back home, your iPad will automatically switch back to Wi-Fi. So if you’re traveling on business or relaxing in a coffee shop, you’ll be able to go online with your iPad 3G without having to hunt for an available Wi-Fi network…well, as long as you can can get a signal, anyway.

And here’s another thing the 3G iPad has that the Wi-Fi version doesn’t: GPS. While the Wi-Fi-only iPad will do its best to triangulate its position based on nearby Wi-Fi networks, the 3G iPad can get a much more accurate fix on its location, even if it’s nowhere near a Wi-Fi signal.

So, if all that’s true, why in the world would you ever consider the Wi-Fi-only iPad over the 3G model? Well, let’s see…

3. 3G is nice, but it’s not cheap
For starters, the base price of the 3G iPad is $130 more than the Wi-Fi model. The 3G-enabled iPad 2 with 16 GB of storage, for example, costs $629, versus $499 for the Wi-Fi-only version. Same goes for the 32 GB iPad ($729 for 3G, or $599 without) and the 64 GB model ($829 for 3G, $699 without).

Even if you do decide to splurge on the 3G iPad (either for yourself or someone on your holiday shopping list), you’ll still have to pay for 3G data service. AT&T, for example, charges $15 a month for 250MB of 3G data, or $25 a month for 2 GB.

Related: How big is a gig (or GB), anyway?

The cheapest Verizon plan for the iPad, meanwhile, costs $30 a month for 2 GB—and yes, that’s five bucks more than AT&T’s equivalent plan. You can also opt for a $50-a-month, 5 GB plan, or 8 GB for a hefty $80 a month. (Neither Sprint nor T-Mobile offer their own versions of the iPad 3G, by the way.)

And if you’re planning on using the 3G iPad overseas, expect to pay even more—a lot more. AT&T’s international data roaming plan, for example, costs $25 a month for a mere 50 MB of data, or a whopping $200 a month for just 800 MB of data.

4. Two words: no contract
That’s the bad news. The good news, though, is you don’t need to sign a contract for 3G service on the iPad. That means you could pony up for a month’s worth of 3G data if, say, you’re taking your iPad on vacation; then, once you’re back home, you could turn your iPad’s 3G plan off again without having to pay a hefty penalty.

Are there other differences between the Wi-Fi and 3G iPads? Yes, a few. The 1.33-pound Wi-Fi only iPad is a tiny bit lighter than the 3G version, although we’re only talking a couple hundredths of a pound. And while you’ll get about 10 hours of battery life on both iPad models while using Wi-Fi, expect only nine hours of juice if you switch to 3G.

So, which one should you get?
Well, that depends, of course. Personally, I opted for the Wi-Fi-only iPad, mainly because I use my iPad at home—and over my local Wi-Fi network—about, oh, 99 percent of the time. When I head out into the city, I generally leave my iPad behind and take my iPhone instead. And by saving $130 for a cheaper, Wi-Fi-only iPad, I felt better about coughing up $699 for the largest 64 GB model.

That’s great for homebodies like me, but what about business travelers, mobile mavens, and other jetsetting road warriors? If your giftee tends to spend a lot of time in hotels, airports, and other non-domestic venues, the iPad 3G might be the best option—and given the high price of for-pay Wi-Fi hotspots (think $10 a day, give or take), the pricier 3G iPad might actually end up paying for itself.

Still deciding on whether to give the iPad 3G or the Wi-Fi-only version as a holiday gift? Send me your questions!