If the iPad didn't exist, the biggest response to the "What sort of tablet would you use" would be "None."
If we were to enter some sort of alternate-reality universe where the iPad had never existed, I doubt, sincerely that any of the other devices listed in this silly poll would exist either, seeing as they all - to a greater or lesser extent - essentially copy the iPad's form factor and physical characteristics. I never had the slightest interest in buying one of the various "Slate" tablets powered by Microsoft Windows. I guess the closest might have been either the Amazon Kindle or B&N Nook, which at least provide unique reading capabilities in a price and form factor that is appealing.
I don't "need" any of the other tablets for the simple reason that all they do is replicate, in a slightly more portable manner, albeit with a worse keyboard, that which I can already do with a laptop or desktop computer.
The iPad, however, is different. Not only thanks to its incredibly broad selection of high-quality Apps, but also thanks to its seamless integration with the iTunes library that already existed on my computer. The way it works with my AppleTV and my iPod Touch. Nothing from Samsung or RIM can do that now - and nothing from Samsung or HP or RIM will ever be able to do that.