Walmart offers the refurbished Vizio 55" 120Hz 1080p LED-Backlit LCD Smart HD Television, model no. E550i-B2, for $399.99 with free shipping. That's $100 off list and the lowest total price we've seen. It features a native resolution of 1920x1080 (1080p), 120Hz refresh rate, full-array LED backlight, SmartTV Internet applications (including Netflix, Hulu Plus, YouTube, and more), WiFi, USB, and four HDMI ports.
Note: A 90-day warranty applies, but it's not clear who provides it.