Do note "Agressive" geometry does not equate to instability. My Habanero classic road bike with 23mm tires on it runs straight as an arrow down the road, is very forgiving, descends in a very confidence inspiring fashion, and goes through corners and climbs much nicer than my touring or cyclocross bikes.
A well engineered bike with the correct tubing for size will be stable and enjoyable regardless of "aggressiveness".