Today's multifaceted cell phones are terrific—until they shut down right when you need them the most.

The problem is, it's not always easy to tell which handsets will have the best endurance. Battery life varies widely from model to model, and—especially—from network to network. Traditionally, the battery life champions have always been 2G GSM devices on AT&T and T-Mobile. Many offer 8 or 9 hours of talk time on a single charge.

But CDMA handsets—meaning just about every recent Verizon or Sprint model—offer just 4 to 6 hours of talk time before needing a recharge. (Few 2G-only CDMA handsets are still sold today, but even those sucked up power compared with their GSM brethren.) 3G HSDPA handsets from AT&T tend to consume even more battery life. Some recent models we reviewed lasted a little over 3 hours, although many can squeeze 4 or more hours of talk time into a single charge.

Still, there's one possibility worth considering: Maybe your current cell phone just needs a new battery. When you first took it home, did it last longer? Many handset batteries begin to lose their capacity for charge after 18 to 24 months. That's even true of today's lithium ion designs. Replacement batteries can cost as little as $20 from third-party vendors. If you're still sweet on your current phone, this is a good way to go.

If not—or if it's just time for an upgrade—check out our top choices for cell phones that can go the distance. For each of the four major U.S. carriers, we've got one feature phone and one smartphone pick.

Motorola MOTO Z9 (AT&T)
The Z9, a jewel-like slider version of the company's powerful RAZR2 V9 handset, offers crystal-clear voice quality. That's not just hype, either, since the Z9 includes Motorola's built-in CrystalTalk noise-canceling software. It lasts over 10 hours in 2G mode—though expect that number to plummet in 3G mode, as is true with all HSDPA handsets.

Nokia N82 (AT&T, T-Mobile)
The Nokia N82 is one of the Finnish company's best smartphones. Along with excellent battery life, it packs a 5-megapixel camera with a Carl Zeiss lens and a Xenon flash. It's easily the best camera phone we've tested to date. In addition, it's a great game machine, has a GPS radio, and—since it's unlocked—works with both AT&T and T-Mobile SIM cards, as well as prepaid SIM cards overseas.

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Sanyo PRO 200 (Sprint)
This inexpensive voice phone for Sprint doubles as a next-generation Nextel push-to-talk handset. It supports Sprint's new EV-DO Rev A data network, has a high-resolution 320-by-240-pixel screen, and weighs just 3.4 ounces. And it's got one of the loudest and clearest phones out there—not bad for a slim CDMA phone that lasts over 6 hours on a continuous phone call.

Motorola Q9c (Sprint)
The reason this handset has good battery life is obvious the moment you lay eyes on it. Sprint, in its infinite wisdom, has decided to make the Q9c's normally "extended" battery standard. That's great for endurance: The Q9c lasted almost 7 hours on our talk time rundown test. But the device looks rather odd, since the larger battery pack destroys the slim lines of Motorola's RAZR-style smartphone. Except for that, the Q9c is an outstanding handset.

Motorola RAZR2 V8 (T-Mobile)
The RAZR may feel like old news, but don't overlook today's updated RAZR2 V8 models. The T-Mobile version is a good buy and offers stellar battery life for such a slim and svelte handset—over 10 hours of talk time. It also features top-tier voice quality and reception, and even comes with a decent Web browser.

T-Mobile Shadow (T-Mobile)
At its introduction, the Shadow was something of a disappointment, since its custom Windows Mobile interface overhaul didn't really live up to expectations. Nonetheless, it's a stylish device with a large screen, a Wi-Fi radio, robust e-mail compatibility, and excellent video performance. It lasted almost 11 hours on our talk time test.

LG VX5400 (Verizon)
LG really nailed it with the VX5400, a feature phone that offers crystal-clear voice calls, an unobtrusive design, and excellent battery life. Perhaps best of all, it's free with a two-year contract from Verizon, which makes it an easy recommendation for anyone looking for a basic but capable handset.

BlackBerry Curve 8330 (Verizon)
Our Editors' Choice for smartphones on Verizon, the Curve 8330 packs in everything that's good about today's BlackBerrys in a smaller, sleeker form factor than that of the company's more business-oriented 8800 series devices. The 8330 Curve offers a 2-megapixel camera, a comfortable keyboard, battery life approaching 6 hours of talk time, a built-in GPS radio, and BlackBerry's legendary push e-mail.

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