Very cool. You should check out Jin-Roh: The Wolf Brigade if you haven't already. Those iconic helmets will stick with you forever.
Nice. Very nice. I've made a few helmets myself that I should post up soon. One of them based on the first design while the others are more on my own imagination.If you're doing this on a computer, try placing lines along key features of the helmet so that you can keep them in place when you draw the front view. It'll give it all a more solid 3D look.
Oh, and that Jin-Roh reminds me of the Helghast armor from Killzone. http://fc05.deviantart.net/fs47/f/2009/220/3/6/Helghast_units_by_avenger09.jpg
Yeah lol, I thought the same thing when I first saw the previews for Killzone. Don't think about posting stuff Red, just do it like a pair of Nikes.In Sai I think you hold shift and make two dots to make a strait-ish line. In Photoshop it's hold shift as well but it's a bit more dynamic. You can also drag the rulers down which is easier. Great for Model sheets.