If I used a desktop PC, I'd probably want it to be this one (I've been laptop only for a few years, but I'd love this on a VESA wall mount with a touch screen).
HP's Z1 is a workstation built into a 27" screen, in a way IT departments and users will love.
For a home PC, an all-in-one PC is an ideal solution; a screen that's big enough for movies, often a touch screen so you don't have to pull out a keyboard to look at photos or browse the Web, and only one cable to deal with. That would be just as useful at work, especially with desk space coming under pressure as companies try to save on rent by squeezing more people into smaller spaces (hot desking and being more flexible about starting new projects quickly are also less convenient with the multiple boxes and cables of traditional desktop PCs). But consumer all-in-ones don't have powerful processors and graphics cards, because they're designed for casual gaming and multimedia, and they're hard to service and support. If the screen fails, the whole PC usually needs replacing; if you want to add more memory or a larger hard drive, cracking open an all-in-one is far harder than opening a desktop case.
HP has paid attention to all of those issues and produced the Z1. Read the rest of my first look at the Z1 on ZDNet.