Engadget has the early comparison chart out of the big-name tablets on offer so far including today’s entrant, the HP TouchPad. Keep in mind that only one of these tablets is actually shipping, but even the promise of so many different operating systems, screen sizes, and feature configurations is enough to set one’s head spinning. It almost makes the PC/Mac debate laughable. Two operating systems? With Windows 7 devices on the horizon, we’re at five and counting for the tablet OS tally. That’s a lot of opportunity, and a lot of potential chaos for developers and content producers.