If the x86 version has sufficient horsepower, they could present the iPad with a serious high-end challenge, because there's a lot of software I like on my Windows box that I'd love to be able to use in a tablet environment (without needing any more functionality than mouse emulation), not to mention a goodly number of USB devices that interface with same. That would substantially reduce my iPad envy.
And thicker/heavier. Plus fan noise. And several hundred dollars more expensive.
It'll be interesting to see if the Surface Pro feels more like an iPaddish-tablet or more like a traditional PC-ish tablet. Unless it's really good at what it does, I think it can easily end up doing more harm than good to Microsoft through Surface brand dilution, consumer confusion (x64 vs ARM, which apps run where), etc.
