Competition - 50/13 top, 34/28 low. That will get me there fast, but get me up any hills on the way.
Gran Sport - 46 and a close ratio 12-21. It's set up as a city bike, no need for hills.
I find I always ride in the same gears: 50/16 on the Comp, and 46/14 on the Sport. That's 82.5 and 81. It's nice to have that 100 inch gear though, for when you feel frisky.
I like the biggest spread possible, so I can go anywhere - any recreational ride around here involves steep hills. And that's how I gear all the bikes I build for various people. On the Comp, I've crowded all the gears at the high end, and then added a bailout gear - 13-14-15-16-17-18-28. I am going to do that to the Sport as soon as I gather the parts.