Everybody's talking about tablets, especially those single-pane capacitive touchscreen ones more specifically known as "slates." The iPad is the biggest newsmaker, but there are lots headed our way (most with built-in webcams). Here's how they measure up, spec-wise:
Updated: We've added Lenovo IdeaPad U1 and Archos 9 Windows 7 edition—see below for more details.

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As you can see, they have different strengths and weaknesses, some of which will become more clear in the coming months as we learn more about each tablet. (That Dell Mini 5 is especially inscrutable right now.)
The iPad has the most storage, cheap 3G, the time-tested iPhone OS and its mountain of apps, and a serious amount of Apple marketing juice behind it. But it's also famously lacking features common to the other tablets, such as webcam and multitasking (only first party apps like music and email can multitask). The Notion Ink Adam is perhaps the most interesting of the bunch, with its dual-function transflective screen from Pixel Qi: It can be either a normal LCD or, with the flick of a switch, an easy-on-the-eyes reflective LCD that resembles e-ink. Its hardware is also surprisingly impressive—but it remains to be seen if Android is really the right OS for a 10-inch tablet.
The Dell Mini 5 and forthcoming Android edition of the Archos 7 tablet are two of a kind, almost oversized smartphones in their feature sets. Is an extra two or three inches of screen real estate worth the consequent decrease in pocketability? Perhaps not. And finally, there's the maligned JooJoo, formerly the CrunchPad, a bit of an oddball as the only web-only device in the bunch. It doesn't really have apps, can't multitask, and pretty much confines you to an albeit fancy browser, sort of like Chrome OS will. The JooJoo is also the only tablet here to have no demonstrated way to read ebooks.
Update: The two new additions in v.2 of this chart, the Lenovo IdeaPad U1 and Archos 9, are both unusual. The Windows 7-powered Archos 9 has been available since September, is the only slate here that lacks multitouch, and is the only one with a HDD instead of solid state memory of some kind. It's more related to the older tablets, but there's no keyboard, just a 9-inch touchscreen. It doesn't even have specific apps like the HP Slate's TouchSmart, it's just a Windows computer.
The Lenovo IdeaPad U1 is even weirder, in that it's actually two computers—the specs listed in the chart are for the tablet detached, but when it's attached to its base, it switches both hardware and software. In its attached form, it's a Windows 7 laptop with a full keyboard and trackpad, Core 2 Duo processor, 4GB of memory, eSATA, VGA- and HDMI-out, and all the other amenities you'd expect from a modern thin-and-light. We just have see what it's like when it ships in June.
Data Sources:
Apple iPad: [Gizmodo]
HP Slate: [Gizmodo, GDGT; Tipster]
Fusion Garage JooJoo: [Gizmodo]
Notion Ink Adam: [Slashgear]
Dell Mini 5: [Gizmodo, Gizmodo]
Archos 7 Android: [DanceWithShadows, Gizmodo]
Lenovo IdeaPad U1: [Lenovo, Gizmodo, Gizmodo]
Archos 9: [UMPCPortal, Archos]
A quick word about "slates" vs. "tablets": These are tablets, and it's a word we prefer. The sad fact is, it's overused. There's no way to say "tablet" without including every godawful stylus-based convertible laptop built since 2002. (Thank you, Bill Gates!) And even the new touchscreen tablets come in single-pane and keyboard-equipped laptop styles. So "slate," good or bad, is the more apt term.