I would say one of my favorite breeds is the Brown Leghorn. There are several varieties, but I think I like the Single Comb Light Brown Leghorn best, because the colors of the rooster are very beautiful.
The Brown Leghorn will lay about 6 eggs a week on average in a year, and they are a great breed for free ranging. They can fly short distances to get away from predators. The brown is better than the white for blending with the environment and avoiding predators.
Leghorns have the best feed to egg production ration. In other words, they eat less and produce more eggs than other breeds.
If you want eggs with the lowest cost, the Brown Leghorn is a great choice. This is not a good breed if you want meat, however.