You don't need to spring for a touch-screen notebook or some sort of all-in-one PC to take advantage of Windows 7's multi-touch capabilities. As CrunchGear reports, all you have to do is grab a display like Acer's new T230H.
The T230H looks like any standalone 23" monitor—quite possibly because it is one. Acer says the display has a TN panel, 1920x1080 resolution, 2-ms response time, 80,000:1 contrast ratio (of the dynamic kind, we'd wager), and 300-cd/m² luminosity. Oh, and there are built-in speakers. You'll be able to hook up the T230H to your PC via a choice of DVI, HDMI, and VGA connectors, but you'll need to plug in an extra USB cable to use the touch functionality.
Speaking of which, Acer boasts that the T230H lets users "rotate images, flip pages, pinch, and draw on the multi-touch screen with simple hand gestures." The product description also mentions working with "increased speed," although it says nothing of how quickly your arms might get tired from pawing at a desktop monitor all day.
Acer doesn't quote pricing yet, but we'd expect the multi-touch support to incur a premium over plainer 23" offerings. For reference, the cheapest 23" Acer display on Newegg right now, the P235Hbmid, will set you back $179.99 with free shipping.