I wear Engineer-style (Carolina brand) slip on work boots, high like a cowboy boot, but with a buckle on the side. They are made for factory work and have solid soles and thick leather. They were very stiff at first.. I tested them out a few years ago by kicking my rear wheel out while going 50 mph. The boots saved my ankles, and I've been wearing them since (about 9 years). Had them resoled once. Red Wing makes a good boot too.
I avoid steel tip boots. I used to ride with a pair of steel toes but they cut into my foot when I shifted and made my toes really cold on cold days. I genereally avoid laces, could become undone and caught in the chain. Tall boots are nice to tuck pants into on cold days, plus keeps grease and oil off bottom of pants. Mine are not insulated, but a pair of wool socks and the occasional coating with mink oil keeps my feet pretty warm and dry.