HP's Slate has received the most buzz of any so-called iPad competitor (keeping in mind the irony and/or painful realization that we're playing into Steve Jobs's hands, since the Slate was announced well before the iPad), but it had essentially a different philosophy. The iPad is a scaled-up smartphone; it runs a mobile operating system, complete with mobile apps (iPhone OS), as well as a mobile (albeit high-speed) processor (Apple A4, rumored to appear in the next iPhone). The HP Slate, on the other hand, is a scaled-down laptop; it runs a full-bore operating system (Windows 7), complete with PC software, as well as a full-sized (albeit low-power) processor (Intel Atom, the standard netbook processor).
But that was also the source of the Slate's mystique--everything the iPad couldn't do, the Slate could. Flash video (including Hulu)? No problem. USB-in? HDMI-out? Slate had it, iPad didn't. That came with trade-offs; the Slate's battery life was projected at half the iPad's, and nobody has much confidence that Windows 7 would be as good a mobile, touch-based operating system as iPhone OS. Every previous tablet has been a scaled-down computer, and none have achieved mainstream success.
So maybe it's not that surprising that, as Techcrunch is reporting, HP may have killed off the project. Apple is proving that a scaled-up mobile OS is the path to a successful tablet, and what do you know, HP just happened to purchase a well-regarded touch-based mobile OS in Palm's WebOS. This is exactly what we'd hoped would happen--a WebOS tablet would have a lot of advantages over the iPad (notably the best mobile multitasking out there).
This is all unconfirmed--I fired off an email to HP, but they haven't gotten back to me yet. In the meantime, let's hope HP really is axing the Slate in favor of a WebOS tablet. Maybe some collective thought power will convince the company to go for it.