In my personal computing experience, the main value of a rack is still the density, as it is in the datacenter. Moving one or two ATX PCs, a UPS, and switch int

In my personal computing experience, the main value of a rack is still the density, as it is in the datacenter. Moving one or two ATX PCs, a UPS, and switch into a half height rack isn't that much of a win (compared to the floor and/or basic shelving). But double that much into a full height rack is. You don't need strictly rackmount hardware either. I just have a pair of non-rack SUA1500's sitting next to one another on the solid bottom built into the rack (not even a movable shelf). The battery type is much more common than the rackmount versions. Case wise I'd just recommend 4U all the way for full size cards, coolers, and fans. Smaller fans make more noise. Also just spend the money on cases with hot swap disk bays for any machine you plan to have more than a few drives. You'll end up wanting them sooner or later, and it's nicer to run the SATA cabling once with how cramped rack cases can get in places.