Why compromise on the single thing that affects the quality of your ride more than anything else just to save an amount of weight you won't notice? Get a Ti spring and you are talking 1/2 a pound. Take the rest out of your post, bars, stem, saddle, cranks if you care, but get the best feeling and most reliable suspension you can. You can also save a lot of weight running 2.0 tires and V-brakes but that's a pretty bad idea too.
If anyone would like to argue that an air shock works just as well as a coil, bring your air equipped nomad and run it back to back with my coil fork and shock. It's night and day.