So what happened when legions of Apple fans were faced with being unable to change out the batteries on their beloved notebooks? Did angry mobs descend on Cupertino? Not exactly. After the initial shock wore off, we began to ask ourselves how important removable laptop batteries actually were.

There are good arguments for removable notebook batteries, especially if you compute on the go a lot. Power outlets are frequently unavailable in locations such as conference rooms, convention centers and aircraft. Power access is improving in newer facilities but it is still easy to find yourself without power. Having the security of the second battery in your bag makes the quest for power a little less panicked. Also, replacing a battery that has outlived its hardware life requires no downtime. A sealed battery has its advantages too, though. It can provide more power for the same weight/space as a removable battery, because you aren’t sacrificing some of the footprint to the hardware and case to make it removable. Your onboard battery will thus get you further with no need for extra power (or to carry around the weight of the back-up).

This debate was front-and-center in my mind when I purchased my latest computer, a MacBook, last April. My choices were narrowed down to a white MacBook with a removable battery, and the MacBook Air that has a sealed one. (Obviously these machines have a lot of other major differences, including their prices.) I was finally convinced to discard the battery difference as an issue when my geek husband pointed out that I rarely if ever used the backup battery that I had for the machine I was replacing. I realized that the spare battery was more of a security blanket that I hauled around than a necessity. Although I eventually purchased the white MacBook, I haven’t felt the need to buy a spare battery for it yet.

The reality is that only a small percentage of notebook users do purchase and use extra batteries. Apple seems committed to this path, and Dell is also trying the concept out. Others may follow.

But heavy battery users are not completely out of luck, and we aren’t all doomed to a future of using our notebooks for four hours at a time. An accessory market has sprung up for external batteries for MacBooks. While not as convenient to use as (and definitely more expensive than) an onboard battery, they do fill that need for people who must have additional power.

We should remember that technology advances. Batteries will continue to improve and soon will be easily capable of getting a notebook through an entire workday. New aircraft are being built with in-seat outlets to power passenger electronics through long flights. Maybe Apple will even realize that there is money to be made by offering its customers the option of a battery upgrade at purchase.

Do you have a spare notebook battery? Do you use it?

The Mini 9 is available for order immediately, at a base price of $349 (though I suspect most interested web workers would go for options that put it in the four to five hundred dollar range). At that price, it’s practically an impulse buy (and I’ll admit to feeling impulsive myself – it might make a good tester for IE8 rendering, if you need an excuse). For that price, you get what appears to be a reasonably capable machine, though there are clearly compromises.

$349 gets you a box with an 8.9 inch 1024×600 display, an Intel Atom CPU, 512MB of RAM, and a 4GB solid state hard drive. 802.11g is standard, as is the black case – you pay extra for white, or for Bluetooth connectivity. The base price includes Ubuntu as the operating system, and this version is showing as ready for pre-order but not for ship. If you go up to $399, you get Windows XP and immediate availability, as well as an 8GB solid state drive. The top end of customization is 1GB of RAM and a 16GB SSD. The box weighs in at about 2 1/2 pounds, again depending on options.

In a move that should resonate with web workers, Dell has done a deal with online storage favorite Box.net – The Dell comes with 2GB of storage, and custom plans if you need more. That’s double the storage of the normal free Box.net account, and the 10 and 25GB plans are priced much lower than Box’s standard pricing as well.

Dell certainly isn’t the only one promoting small, easily connected boxes for the mobile worker. Nor is this by any means a computer you’d use to do offline work. But given their reach, it might end up being a “second device” for a great many web workers.