The 27" ... well, I upgraded my wife's side of the office to one earlier this year (pre-Thunderbolt) and there's a limit to the depth of my pockets. Besides which, my desk is already dwarfed by the 23" panel (and said desk is an obscure 1970's Swedish designer item, not something I'm likely to replace in a hurry).
Backups: Time Capsule for on-site, 1Tb pocket hard disk for on the road, and Dropbox as a sync solution and if-all-else-burns-to-the-ground fallback.