UPDATE: For those of you who are interested in comparing your hash-fast mining rig to FLOP-fast supercomputers out there, I just recently noticed that Bitcoin Watch reports both the network's hashrate per second and its FLOP rate per second. I don't know how they derived the second figure (see "User:"jimrandomh's comments on the difficulty of comparing hash-type and floating point computations).

Dividing the two, it's implicitly assuming ~12,700 floating point operation equivalents per computed SHA-256 hash. For the 2+ users among us that have a 1.6 GHash/sec rig, that makes it equivalent to a ~20 TFLOP/s supercomputer, comparable to the state of the art in supercomputing circa 2001-2002.

Again, I make no pretense of vouching for the 12,700 FLOP/SHA-256 hash figure.