Too much thinking here...
The quick and easy recommendation is to shift into a gear that lets you pedal at 90-100rpm under all conditions--smaller chainring or larger rear cog on hills, larger ring or smaller cog on flats and downhills. There's some slack in that, but it works well for most people. You're obviously strong, and you'll soon develop a feel for it. Cadence counters aren't of much use in everyday riding, IMO.
Also, a minor correction: If you were pedaling slowly while everybody else was spinning like crazy, you were in a HIGH gear, not a low one. A lot of people mix that up. When you're pedaling fast against low resistance, that's a low gear. Pedaling slowly against high resistance is a high one.
Last edited by Velo Dog; 08-29-10 at 07:34 AM.