9. HP EliteDesk 800 G1
Desktop PCs have been fading for years in favor of laptops and all-in-ones, but using a desktop does let you use any monitor you want. Traditional desktops take a lot of room on or under a desk, but there's a solution to that challenge: an ultraslim PC like HP's EliteDesk 800, which takes almost no space yet offers the computing power you need.
The EliteDesk 800 uses a 3.2GHz Core i5 processor, has 4GB of RAM (expandable to 16GB), a rewritable DVD drive, and a 500GB hard drive in its 10-inch-by-10-inch footprint and 2.6-inch height. Its ports are generous: one Ethernet, four USB 3, six USB 2, two PS/2, one VGA, and two DisplayPort.