Dividing Apple's desktop line into three neat divisions--Mac mini, iMac and Mac Pro--still leaves you with enough options to make your head spin when it comes time to plunk down your money for new hardware. Here's a run down of what to expect when you go shopping for a new desktop Mac.

Mac mini: Phenomenal cosmic powers! Itty-bitty living space!

In 2009 the Mac mini, along with its portable cousin the MacBook, went from a mediocre-performing entry level machine to a seriously powerful piece of machinery. The most recent improvements to mini make it a better value and easier to use than ever before.

Starting at $699, the Mac mini touts a 2.4 GHz Intel Core 2 Duo microprocessor, 2GB RAM, 320GB hard disk drive, 8x SuperDrive and Nvidia GeForce 320M graphics. You can almost think of the Mac mini as a MacBook without a screen, the specs are so similar. The 2GB of RAM are pretty scant, but Apple has made it easy to upgrade the Mac mini to up to 8GB of RAM by making the RAM sockets accessible via an easily-accessed bottom panel - a first for this product (in the past, you'd have to pry the lid open).

The Mac mini is a little more media-oriented than the MacBook is, however. You get an SD card slot, for example, for getting files from digital cameras and camcorders. Four USB slots make it easier to connect peripherals, and a FireWire 800 and Gigabit Ethernet port make transferring data fast and easy.

The Mac mini's built-in HDMI port also make it suitable for connecting to an HDTV, if you'd like to use your Mac as a media center, either through Apple's built-in Front Row application or a variety of third-party applications that help you serve up media on your Mac. If that's not important, an adapter can be used to convert that HDMI signal into something your monitor can display; a second display interface is also included (Apple's mini DisplayPort), so you can hook up your Mac mini to an Apple LED Cinema Display or a second monitor.

The usage case for the Mac mini varies dramatically. At first look you'd think it's a machine only suitable for casual use, and if that's your expectation, you're dead wrong. In fact, the Mac mini is an amazingly competent general use computer (just like the MacBook) that's equally adept around the house or in the office. It's less suitable for heavy-duty media editing; for video, 3D graphics or pro audio, it's probably work looking at an iMac or Mac Pro instead. But you'll be pleasantly surprised at how well the Mac mini runs most games - it keeps up with just about anything from Steam that we throw at it, for example.

Here's one final example of where the Mac mini is easy to underestimate. Turns out that Apple's Mac mini with Snow Leopard Server system, available for $999, is its best-selling server hardware. Moreso than the soon-to-be-discontinued Xserve. Don't discount that tiny aluminum box. Just like the Genie in Disney's Aladdin movie, it may be resigned to itty-bitty living space, but it has phenomenal cosmic power.

The iMac: Wide Open Spaces

The iMac is the Mac that put Apple back on the map. When Steve Jobs introduced the original iMac in 1998, it was a petite gumdrop-shaped system with a built-in 15-inch CRT display. Now it's a gorgeous wide-screen flat panel system available in 21.5- and 27-inch that sets the standard for cutting-edge desktop industrial design. What's more, it's an absolute powerhouse--some of Apple's highest-performing desktop hardware is in the iMac line. But with so many options to choose from, figuring out the best iMac to get is a daunting task.

Under the hood of the iMac are a variety of processors (Intel Core i3, i5 and i7 models are all represented here); support for up to 16GB of RAM; 500GB to 2TB of storage capacity; and different kinds of ATI Radeon HD graphics to achieve the fastest 3D graphics rendering possible. From $1199 to $1999, there's an iMac to fit modest to robust budgets for a desktop Mac. How much you want to spend will depend on your needs.

That diversity takes some careful scrutiny to figure out, based on your budget and your needs.

The Core i3 processor-equipped iMacs--available in different clock speeds, on both the 21.5- and 27-inch models--support "HyperThreading," which helps the Mac better manage a lot of work all at once, but they don't support "Turbo Boost," which can increase processor speed to give a little push to how fast data is processed.

The 27-inch iMac equipped with a 2.8GHz i5 chip supports Turbo Boost, but not HyperThreading. That i5 chip also has a quad-core architecture, though, so more work can be distributed for simultaneous processing.

All the other i5 models support both Turbo Boost and HyperThreading.

On the high end, the 27-inch 2.93GHz iMac supports both HyperThreading and Turbo Boost. The Intel Core i7 chip is quad-core, like the 2.8GHz, so you'll see further performance enhancements in apps designed to put multiple CPU cores to the test, such as video editing apps, scientific software, some image editing software, and any other software designed to leverage some of Snow Leopard's underlying frameworks.

One thing we love about the 27-inch iMac is that it doubles as a monitor. That's right: using a Mini Displayport adapter cable (sold separately), you can connect this iMac to other computers and use it as a display. So if you want to share your desk with a PC or another Mac but don't want to clutter it up with another monitor, there's another option that will improve the utility of your workspace and extend the usefulness of your iMac.

For gaming, basic productivity applications, office apps, internet access and other general purpose use, buy as your budget dictates; you'll see incremental improvements the more you spend.

Once you're into the realm of the 27-inch models, you're solidly in the mid-to-high range of Apple's desktop hardware. Here you breathe the rarified air of the Mac media professional--digital videographers, filmmakers, professional musicians, graphic designers, 3D artists and others who make a living using their Macs. The 27-inch systems are fantastic home machines, too, and are definitely reasonable enough for households to afford. Let your conscience--and your wallet--be your guide.

Mac Pro - Brutal efficiency

Standing like an aluminum clad skyscraper, the Mac Pro is easily Apple's most intimidating-looking computer. Its design is a paean to the Bauhaus design aesthetic that permeates so much of Apple's product line, in which form so ruthlessly, yet elegantly, follows function. And starting at $2499, it's also Apple's most expensive.

The Mac Pro is solidly in the workstation space for Apple. Neither the design nor the function of these systems is really necessary for a casual home user or event most business users, who will be better off with the tiny Mac mini or the elegant and sophisticated iMac. Where the Mac Pro comes in handy is in professional environments where expandability is an absolute must.

A lot of that has to do with how the Mac Pro is built: Inside are Intel Xeon processors, built to be industrial strength, with power and data management capabilities that can't be matched by the processors on any other Macs. There's room for up to four SATA 3.5-inch hard disk drives with independent channels; with Apple's 2 TB drive mechanisms, that's 8 TB of internal storage (and with third party drives now available in 3 TB, that's conceivably up to 12 TB, a staggering number).

Two optical drive bays (only one of which comes equipped from the factory). Support for single or dual-processor configurations - including six-core processors (for up to 12 cores per machine).

Plus all the expansion options--four Firewire 800 ports, five USB 2.0 ports, dual Gigabit Ethernet connections, optical audio in and out, support for two video cards, plus two additional cards--and everything about this Mac screams "heavy duty."

Mac Pros commonly see use in heavy-duty production environments like professional audio and video production companies, in enterprise IT environments, and by people who want a system that has the maximum amount of expandability with the minimum amount of fuss. After all the Mac Pro is built to get in and out of easily and quickly: pop a tab on the back and you're in; new drives slide right in on trays that are included with the system; memory can be installed without any fuss; even new video cards pop in with little more than a single screw to turn to fix in place.

There are a few of us with enough technolust to want a Mac Pro at home, too. But before you buy one, ask yourself this - are you comfortable with the aesthetic statement it makes? It's like parking a Hummer--the original behemoth, not the smaller ones--in your driveway. It definitely broadcasts a message about what's important to you. An industrial-strength message. But at the end of the day, if you're looking for brutal efficiency without compromise, the Mac Pro is the model to beat.