MegaMacs offers the refurbished Apple Mac Pro Xeon Quad-Core 3GHz Workstation for $429.99 plus around $27 for shipping. That's $30 under our refurb mention from a month ago (which included software but had less RAM) and the best price we've seen for this model with this configuration. It features two Intel Xeon 5100 3GHz dual-core processors, 4GB RAM, 500GB 7200 rpm hard drive, SuperDrive, and Radeon X1900 XT 512MB video card. Deal ends February 19.
A 30-day MegaMacs warranty applies. Also, an OS is not specified, although one is preinstalled.