There will be 500Gb and 1Tb variants, with the following US pricing:
500Gb HP MediaSmart EX470 (GG795AA#ABA) – $596 (£299)
1Tb HP MediaSmart EX475 (GG796AA#ABA) $745 (£374)
Both systems will be powered by a 64-bit (and therefore WHS v2 compatible) 1.8GHz AMD Sempron processor and come bundled with HP’s bundled Photo Webshare software, including direct links to Snapfish (HP’s Photo Printing partner). The 1Tb system appears to be configured as 2 x 500Gb hard disks, leaving 2 of the system’s 4 drive bays free for extra storage (as well as the 4 free external USB 2.0 ports). The EX470 is configured as 1 x 500Gb, with three free internal bays for future expansion. As you can see from the shot of the system’s rear below, it will be fully headless, with no monitor port.