Asus VivoBook X202E down to $399
This is probably the cheapest touchscreen system available right at the moment (with a Core CPU), and it's actually not a bad little system. Impressively for a cheap laptop, it is part of their Signature line so no crapware (trialware and other garbage is common with cheap PCs). There is some good action over at slickdeals about this system as it has been discounted recently.
I was leaning toward an impulse buy but I don't need a new laptop at the moment. When I do, I'll be willing to spend more for a Core i5, IPS panel and hopefully a higher res display. But this seems awfully competent for the money. It's not technically an Ultrabook but as an under-3lb laptop, it is impressive to find a VGA port (nice to have if you need it but hopefully most people don't), a full array of other ports and you can even replace the battery, hard drive, wireless card (upgrade to dual band N and WiDi for example). Not sure on the ram. But upgrading the wireless to dual N and the HDD to an SSD would make this quite the system.
I found this review helpful: http://www.mobiletechreview.com/notebooks/Asus-VivoBook-X202.htm