Carole, due to the usually high price of boots as well as the fact that my calf size prevents most boots from fitting me, I have built a minimalist boot wardrobe over the past year. (I'm talking about boots, not booties here.)
The first pair I bought was a knee-length cognac colored pair of riding boots with a very small heel. Over the past year, I added a pair of tan suede heeled boots, flat black riding boots, and dark brown, sleek, slightly heeled leather boots. Of those, the boots I wear most frequently are the cognac and dark brown pairs. (The former is more casual, the latter is a bit more sophisticated.)
I hope this helps as you are building up your own collection!