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.