I've got a PS3 and didn't think anything of using it for a MD untill the release of the Playstation Camera. It has a stereo mike and a very high resolution camera for $39.00. Bottom end systems come in at $390 with 40 gig HD, gigabit eithernet, HDMI, Blue Ray DVD, 4 USB ports.
As a MD it makes a good system, Compact and powerful. The economy of scale for this system makes it attractive.