I don't know why, but I thought I'd crank out a polygon helmet. I did it in under an hour (textures included). It's a WWI British pattern (1915) helmet (the famous "Tommy/Doughboy" helmet which was worn by the British through WWII and by the US until the "steel pot" replaced it in 1942).

I wasn't going for photorealism and I did it from memory rather than a photo (though I suppose I could have used one). "Close enough for government work", and again done in well under an hour. Lighting (or attempting to light it) took a good chunk of that hour! :-)

Basically, it was a half-sphere with extruded edges.

Anyway, the advice about using a bump map is relevant. I created a grayscale noise pattern in Photoshop and applied it as a bump map to simulate the gritty finish on many of these helmets. Also, be sure and bevel all sharp edges!

Some nice helmet work on this thread, keep it coming!