Randy wants to build his rough cut cedar fence right with no future stains, but has been told that even stainless steel nails will eventually rust, and that given the price difference he might as well use galvanized.
Actually your choice of nails goes much further than that -- including "plastic nails" that I found in Texas, though these haven't been tested yet for our cold climate. Actually, stainless steel nails don't "rust" rust, but grime that accumulates in the nail hole can flow downward giving the appearance of a rust stain. You can also get aluminum nails that work well with cedar, but of course these are the wrong colour (don?t use aluminum nails with pressure treated wood because the aluminum corrodes under contact with the chemicals in the pressure treated wood) . Hot dipped galvanized will last a long time. The rust usually starts where the hammer hit the head, scraping off the galvanization, so if you are using nails with any kind of coating, you may want to locate a "hammer protector", a little plastic cap that fits over the head of the hammer to prevent it from taking off the finish on the nail. There are new very durable coatings on screws and nails that come in either green (for pressure treated wood) or brown (for cedar) that are worth considering.