We don't call them "smartphones" for nothing.

From e-mail machines like the BlackBerry to svelte handsets like the iPhone, many cell phones today are essentially small computers with microprocessors, gigabytes of memory and the ability to surf the Internet.

So why use a laptop at all? Can't we do everything now on a smartphone?

To test the hypothesis, I tried to abstain from my laptop for a week and rely solely on a smartphone.

Since I'd just been handed a new Palm Pre ($200 with 2-year Sprint contract) to evaluate, I decided to start with that one.

• Click here for FOXNews.com's Personal Technology Center.

• Got tech questions? Ask our experts at FoxNews.com's Tech Q&A.

The Palm Pre is a snazzy, touchscreen phone with two distinct advantages over Apple's iPhone: It has a slide-out QWERTY keypad, and it can multitask like a computer.

In other words, it can run more than one application at a time, such as downloading e-mail or delivering turn-by-turn directions while you're talking on the phone.

The first outing for the Pre was an open house at my daughter's school. I'd forgotten to bring a camera (bad Dad), so I had to resort to the Pre.

Its 3-megapixel camera did a reasonable job. Pictures were crisp and had good color saturation, but it was inadequate when it came to taking quick action shots and it couldn't record video clips.

After class, I found the Pre managed e-mail and contacts rather nicely as I arranged for interviews and confirmed appointments. The phone uses its own software to combine contacts, addresses and calendar listings from Google and Microsoft Outlook — a handy trick.

In spite of the keyboard, however, I quickly discovered the phone's Achilles' heel.

A program called DocView from DataViz comes pre-installed on the Pre. So I downloaded some articles I was working on as attached Word files. Unfortunately, as the name of the program suggests, I was only able to read — not edit — my stories using DocView.

Ultimately, as much as I like the Palm smartphone, I had to admit that it simply didn't have enough available software yet to function as laptop replacement.

So I decided to try the phone with the most available software on the market, the Apple iPhone 3G S ($199 for the 16 GB version with a two-year AT&T Wireless contract).

Apple claims there are over 50,000 supporting applications for its phone. With so many, it can be a chore finding the right ones in the online App Store, but there were countless that proved useful.

Google Earth, for example, was a excellent tool for locating the exact spot of meetings in midtown Manhattan. It even offered street-level views of buildings so that I knew exactly where I was going.

Between meetings, I found I could read books from my Amazon Kindle by using another free application. It even automatically synched the books, so that when I returned home and picked up my Kindle, it was on the page I'd where I'd left off on the iPhone.

When I suddenly realized that I'd forgotten to pay a bill, the iPhone also offered a solution.

Using Mobile Banking on AT&T, a free program developed by Qualcomm's Firethorn, I was able to transfer funds and pay my bill online, much to my relief.

In addition, DataViz just released a version of its software for the iPhone, Documents To Go with Exchange Attachments ($9.99). With it I was able to edit Word files, but only view Excel and PowerPoint files.

Unfortunately, editing Word proved to be an onerous task. The DataViz software was fine, but the on-screen touch keyboard on the iPhone, while an improvement over the previous version, still caused me to make so many errors that I soon gave up in frustration.

Nevertheless, before I abandoned the iPhone, I wanted to try one more task: using it for turn-by-turn navigation to my weekend getaway.

AT&T offers a Navigator service for $9.99 and recently added it to the iPhone. I found it worked fine — until the phone rang.

By picking up the call, I automatically terminated the navigation because the iPhone isn't able to fully multitask.

In other words, I had to choose between missing calls or missing turns. (You can work around this by restarting the navigation while you're on the call, but it's not a safe maneuver to perform while you're driving.)

Finally, I tried T-Mobile's G1 made by HTC ($150 with a two-year contract), another touch-screen smartphone that, like the other two models, can use a Wi-Fi network or cellular data network to connect to the Web.

The G1 uses Google's Android software, and even though it only has about a tenth of the applications compared to an iPhone, it can do most of the same tasks and does a better job handling some.

On my peregrinations, for example, I tried Firethorn's Mobile Banking software, which worked as well as the iPhone version and supported most of the major banks, such as Chase and Citi.

I also tested an amusing but useful free application called Sit or Squat. Essentially, it's listing of nearby bathrooms, including star ratings and photos (yes, photos of commodes).

When we stopped to shop, I used ShopSavvy (free) to check the price of an MP3 player in Wal-Mart. Using the phone's camera, it scanned the bar code and quickly looked online for better prices at other stores. When we were done, another free application led us back to our car in the parking lot.

Of course, I still had to work, so I tried the $19.99 DataViz program Documents to Go. I discovered that this version let me edit not only Word, but Excel files as well.

The G1 also has a bigger, slide-out QWERTY keypad that I could use with two thumbs. It's less cramped than the Palm model's and far more practical than the iPhone touchscreen.

Still, I realized that I would not want to use it to write an entire article, and the DataViz software could only read PowerPoint and PDF files, not edit them. (DataViz promises that capability is coming soon as a free upgrade.)

The final straw, however, came when we arrived at our country destination in the mountains.

That night, I tried a free program called Sky Map. By pointing the phone at the stars above, the screen revealed the names of the celestial objects so that I could tell my daughter we were looking at Saturn, just as if I had studied astronomy all my life.

Dejectedly, I discovered that T-Mobile's cellular coverage in the country was spotty at best. I could occasionally place a call from the porch outside, but a fast wireless data connection was out of the question, squelching any hope of decent Web access while away. (The other two phones also had trouble making a data connection.)

In the end, I only managed to make it 4 days with the smartphones before I gave on my digital expedition and returned to my laptop.

Certainly, if all you need to do is send e-mail and occasionally surf the Web, the latest crop of souped-up cell phones can get you pretty far.

But for some tasks — such as finishing this article — only a full-fledged notebook will do.