The back-to-school season is upon us, bringing with it droves of students stocking up on books, school supplies, and something trendy to wear on that all-important first day back. Notebooks are popular at this time of year, of course, but if portability isn't a priority, desktops can offer substantially more horsepower and flexibility at significantly lower prices. The time is right, then, for another update to our system guide.

It's been almost two months since the guide was updated, and its contents already read like an ancient Babylonian tale etched on stone tablets. Well, maybe not. But things change quickly in this industry, and the last two months have been no exception. Thanks to falling prices spurred by the introduction of new products, we've managed to slip a quad-core processor and a Radeon HD 4870 into our $1,000 Grand Experiment system. The $500 Econobox's gaming chops have been upgraded with a GeForce 8800 GT, too, and our $1500 Sweet Spot build has been lavished with RAID and other high-end luxuries.

To make things even more interesting this time around, we've fashioned a sub-$300 PC based on Intel's new Atom processor. This system won't set any performance records, but it should satisfy users looking for basic, no-frills desktop functionality in the kind of small form factor that easily squeezes into cramped dorm rooms. Read on for all the details on this and other builds in our latest system guide.