Using a mini-monitor for Photoshop toolbars or tracking email is pretty handy, but they're also pricey. So even though DoubleSight's new 7- and 9-inch LCDs aren't touchscreen (like the $230 Mimo 720-S), I like that they start at just $120.
That price gets you the 7-incher, which has a resolution of 800 x 480. The 9-inch models ($160 with detachable webcam; $140 without) can do 1024 by 600. Each uses USB for both video and power—you don't need any fancy graphics card.
What sells me on them, though: they'll also pivot between landscape and portrait orientations. Nice. Of course, you can pick up a full size monitor for less than $150, but if desk space is precious to you, a mini-monitor might be the way to go. [DoubleSight]