With Steve Jobs’ announcement of the Mac mini at Macworld San Francisco, the first thought that came to mind is: “Steve’s got his Cube back.”

Now your first reaction to that might be, “Huh?”, but when you think back to the G4 Cube, it was basically the same thing you’re seeing in the Mac mini, just with a better processor, bigger hard drive, upgraded components, and different packaging. Oh, and one helluva killer price!

There’s no denying that the Mac mini is revolutionary. Apple has proven once again that they can be innovative as hell, and the Mac mini is a (small) shining example of things done right. And sure, while I don’t have one (yet, obviously, since they won’t start shipping until January 22nd), you can bet it’s on my list of many things to get — ASAP.

While many people are looking at the Mac mini as a low-cost entry point to win over all those Windows folks who’ve purchased an iPod and have been noodling about getting a Mac, I see many more uses for it, one of which being something I’m guessing not many people outside of Apple have thought about (but I’ll get back to that in a bit).

The first, and most obvious use, for the Mac mini is as a component in a home theatre system. Since you can add an AirPort card and Bluetooth to the mini, you can stream iTunes to the Mac mini and pipe that through to your stereo system. And since you can add AirPort, you might as well use the Mac mini to share its Internet connection. And since the mini has a built-in DVD player with the Combo and SuperDrive, you can use that to play DVDs on your television. Lots of good stuff here.

Another use I have for the Mac mini is as a small, lightweight server. These things are incredibly quiet (just like the G4 Cube of yore), so if you need small-ish server for tossing up your blog or to act as a file sever between a couple Macs in your home office, here’s your baby. And the best thing is, if you know a bit of Unix, you can run the Mac mini as a headless server and just SSH into and administer the mini.

Oh, and one more thing…clusters and grids.

Yep, you heard it here. And while using the Mac mini as a cluster might sound far-fetched, think about it. While they don’t have a G5 processor, the minimum 1.25 GHz G4 is nothing to sneeze at, especially with a cost of $499. Buy another one, and you’ve got — essentially — a dual-processor system for less than $1000 if you tie them together with Xgrid. And because the Mac mini’s are so small (6.5 inches wide and 2 inches tall), you can pack a lot of these puppies in a room and build a cluster that doesn’t cost an arm and a leg. (Think of the possibilities for an inexpensive graphics rendering farm based on a bunch of Mac mini’s. Would be mighty cool to see, wouldn’t it?)

And yes, I can see where the Mac mini might be an attractive answer to all those Windows users who’ve toyed with the idea of switching to the Mac, but have been riding the fence because they don’t want to toss away all their PC gear and then spend a bunch of money on all new Mac gear. Now you can buy the Mac mini and use your existing PC monitor, keyboard, and mouse along with it and essentially have the Mac you’ve been wanting. I’m not sure if there’s a KVM switch that allows you to share monitors, keyboards and mice between two PCs. If so, I can see where these will be hot items, since you could essentially switch between your Mac mini and Windows PC with a flip of a (KVM) switch.

For me, the Mac mini is more about possibilities than it is about Apple gaining market sure (which I’m sure they will). Slap me if I’m being silly, but Apple’s really hit one out of the park with the Mac mini, and it hasn’t even reached the shelves yet. And while the masses may not have embraced the G4 Cube years ago, the Mac mini is going to have a significant, positive impact on Apple’s bottom line.

What’re your thoughts about the Mac mini? Are you planning to buy one? If so, which model, and how do you plan on using it?