I doubt it Doug.
No matter how you shake it out, tablets/slates are low-end devices -- just like netbooks. The difference is that Windows 7 Starter edition with 1GB of RAM really can do whatever you want it to do -- IF you can tolerate the sluggishness of Windows 7 on a single-core Atom processor with 1GB of RAM!
That said, for $499 you can get a dual-core 4GB Win 7 (x64) with a 160GB HDD which really can do everything you want (though not necessarily swiftly). Not even a $699 iPad can do that. It takes a $999 Macbook to get you there! Microsoft is certainly prudent to look at porting Windows 7 to ARM -- if for no other reason than to hedge their bets that Intel may not be able to keep up with ARM.
Frankly, readers and pundits alike are making way too big a deal of Apple's dominance of the "appliance" market. After all, that is what they do. (Apple makes really slick -- sexy-looking, if you will -- gadgets for which consumers are willing to pay premium prices. These are simply appliances for consuming media. They cannot replace the consumer's MacBook and they will not replace the consumer's PC.
The iPad is really nothing more than the latest generation of the iPod Touch -- but with a large screen. If you are willing to pay a premium for a simple, but powerful appliance (which still needs a desktop computer for syncing) then the iPad is fine. But it is not a Macintosh or Windows personal computer -- nor will it ever be.
I agree with others who point out that Windows needs a tablet-centric UI. That will come soon enough. Ported to ARM or not, Windows "8" will certainly benefit from better kernel modularization but that isn't the key. The key is the System-on-a-chip concept -- which would allow Microsoft to boot Windows 7 using a device as compact as the 64GB iPad. As fast as memory is coming down in price, there is little reason to assume that Microsoft will not be able to deliver such a device -- and sooner than you think.
Microsoft has been supporting ARM processors for years. EVERY Windows mobile phone from 2000 to present runs on ARM architecture. Windows CE, in all of its many forms (appliances, mobile phones, consumer GPS devices), run on ARM architecture. The only "new" thing coming out of this announcement is Microsoft stating that their "main" OS (Windows 8+), their bread-and-butter, will run on ARM.