Some interesting quantitative data from Jim Gray's Distributed Computing Economics:

$1

= 1GB over WAN

= 10 Tops (1012 CPU instructions)

= 9 hours of CPU time

= 1 GB disk space

= 10 M database access

= 10 TB disk bandwidth

Computation/network break-even point is

= 10k instructions per byte of network traffic

= 1 minute CPU time per MB of network traffic

Copied from old blog