I sadly haven't seen the 1970s original, or even the recent BBC remake, although I'm very tempted to get it on DVD.
One series I did catch completely by accident was
The Last Train, - some old cable channel was showing the whole series back to back and I got sucked in for hours, I really enjoyed it.
I have to disagree with Mouseburger, there is ample room for more "collapse of society" in cinema. The "28" and Omega Man spin-offs feature zombies, which inevitably colours any kind of life for the remaining humans. That's fine, but it's often more interesting to explore what happens with completely normal people when they miss a few meals.
And, Reign of Fire was bloody awful, and can't be used as any kind of serious example (you may as well cite "Rats", which was so painful we didn't even write it up!)
Conversely, the genre has been very well treated in literature. For example, I'm surprised John Christopher's
Death of Grass and Niven's
Footfall were never given the big screen treatment. They were written in very different times, but both are essential reading in my opinion.
Like Mouseburger, I'm a massive fan of this genre by the way.