Microsoft Store offers the 4.95-lb. ASUS Transformer Book Flip Signature Edition Haswell Core i5 1.7GHz 15.6" 1080p Convertible Touchscreen Laptop, model no. TP500L, for $649 with free shipping. That's $100 off and the lowest total price we've seen. (We mentioned the 13" model for $50 more three days ago.) It converts into a touchscreen tablet and features an Intel Haswell Core i5-4210U 1.7GHz dual-core processor, 15.6" 1920x1080 (1080p) LED-backlit touchscreen LCD, 8GB RAM, 1TB hard drive, 802.11n wireless, webcam, Bluetooth, 3-cell battery, and Windows 8.1 64-bit.