I have various firewall/router/utility type boxes that do not require much if any storage for their primary purpose other than booting. But I do like to be able to put a more or less standard CentOS/RHEL install on them which takes a few gig. So I normally end up mirroring two small hard drives. Recently VARs have been proposing boxes with a single SSD like the Intel X-25M 40G on the theory that a single drive is simpler/takes up less space/draws less power (all important factors to me).
Any opinions on whether a single SSD is better than a pair of HDs?