I bought a roll of PVF coated brake line at a local auto parts store last year and used it to re-plumb the brakes on my winter beater 88 Olds.
They've only been through one winter's exposure to road salt so its a little too early to know for sure. But so far they aren't showing any signs of rust. The regular zinc (or whatever they're coated with) steel lines would get discolored and often start showing a little surface rust after a winter or two. And often be in need of replacement again after 4 or 5 winters. Especially with the calcium chloride they use on the roads around here ... the rock salt & sand mixture they used to use (and still do on some roads) isn't nearly as corrosive.
On the other hand, I've seen the regular steel brake lines last 30+ years on vehicles that haven't been exposed to road salt. So I guess it all depends on how you plan to use your car. Regular lines will probably be just fine for most applications. But for a car that'll be exposed to salt/calcium, the coated brake lines are probably worth the extra $$. Note that calcium isn't just used for winter ice melting ... some places use it to control dust on unpaved roads. Also note that you have to be a little extra careful when installing the coated lines. Although the PVF is pretty tough, it can still be scratched off (leaving the line unprotected) if it gets scraped up against anything sharp.
Thanks for the intell Ray McAvoy! I think I will probably go with the steel lines since we have really mild winters here in the NW. And if there is any bad road conditions my Chevy II will be staying home.