The pixel-dense Dell XPS One 2710 is one of the best Windows-based all-in-ones available and, barring a new iMac, an easy high-end recommendation.
If you're looking for a lot of screen real estate and enough power for work and play, the HP Pavilion dv7-6b55dx is a good place to start.
Dell's updated Inspiron line has a slightly revamped design, but more importantly still offers workhorse performance for a minimal investment.
If HP's TouchSmart 600 won't at least get you thinking about the idea of bringing a PC into your kitchen, the concept truly has no hope. With well-thought-out touch apps, a wide, easy-to-use array of digital media features, and an attractive, flexible design, HP's new all-in-one is not the fastest new all-in-one, but it has the most comprehensive and compelling set of features of any all-in-one launching alongside Windows 7.