The ASUS zenbooks were pretty damn good as far as I could tell. I've heard decent stuff about the Dell XPS ultrabooks.
Not exactly an ultrabook, but thinkpad x220/x230 was pretty amazing except for the low screen resolution. IPS screen, great keyboard, great performance aside from integrated graphics, space for an mSATA SSD as well as SATA HDD/SSD, battery slice to boost it to 20+ hours, removable battery, and great linux support.