i generally have a high cadence. i'm happiest at +/- 108 RPMs. I can easily find myself riding at over 115-120 RPMs, and have to remind myself to shift into a bigger gear.

to be honest, I was never aware of the actual numbers until i saw the 'virtual cadence' on my Flight Deck.

90 RPMs is an OK start, but shoot for 100.

caveat - I ride mostly in the Netherlands, where there are no hills, but plenty of wind, although my cadence is more or less the same when i'm back in New England.