Best being most efficient use of gold. Some comments in the general section got me thinking maybe I'm not spending my gold in the best manner. A poster said that gold is generally only used for unit upgrades. And I've been using it for damn near everything. I love gold, and can't get enough of it. It's nice when you are making enough to buy factories and such, though usually I hard build those. My main uses of gold are for buying tiles and unit upgrades. Tile expansion is extremely slow in this game, and I do like to speed things up slightly. My main question is about buying buildings. Is it worth it?