I have a Gary Fisher Nirvana that came with a Rock Shox Metro suspension fork. The fork cannot be locked out. Since I ride on paved roads 90% of the time, I'm considering replacing it with a rigid steel fork. Will I notice the weight savings and increased efficiency? I'm not concerned with speed and I'm content commuting at 15 mph, but I often feel like the suspension fork is creating extra work and effort both on flats and hills.

If anyone has changed suspension for rigid forks, I'd appreciate your input.