Brooke Crothers at C|Net seems to think that Apple is vulnerable to Windows 8 hybrid devices and touchscreen laptops. I guess time will tell but I've never had the urge to touch my laptop screen. These seem more gimmicky to me than anything else. And based on some of Apple's patent filings I wouldn't be surprised if they've tried this and decided keeping laptops and tablets separate is the better way to go.
http://news.cnet.com/8301-10805_3-57504849-75/microsoft-spies-apple-vulnerability/
http://news.cnet.com/8301-10805_3-57504849-75/microsoft-spies-apple-vulnerability/