This is difficult in many ways. For one thing, when you say 'understanding of punk', do you mean the history of punk, the structure of punk, the lifestyle associated with punk, or the general lyrical/musical thrust of the music nowadays?
I'm going to compose this list, rather than as an overview of punk, more as a 'beginner's introduction to punk'
If what you're looking to do is introduce a new person to Punk, there are several more modern variations you can use as kind of a feeder to get them to understand the older bands, and these are:
-Street Punk
-Ska Punk
-Punk Rock/ Pop Punk
Depending on the type of person you are letting hear the music changes the type you want to get them to listen to. For example, someone who listens to Heavy Metal, Speed Metal, or Hard Rock would probably most easily associate with Street Punk, while someone into Pop, Emo, or Dance would more easily be swayed by the Pop Punk and Punk Rock varieties. A few examples of each include:
Street Punk- The Briefs, Anti Flag, The Bastards
Ska Punk- Less Than Jake, Mighty Mighty Bosstones, Rancid, some older No Doubt
Punk Rock/Pop Punk- Sum 41, Bowling for Soup, Green Day
Most of the bands in the above listing are easy to find and have at least some amount of mainstream commercial success, but there are many others within those genres that would work just as well.
Once you've got them hooked, you can stop worrying so much about genre restrictions and go all out. At the next stage, you may still want some mainstream recognition, but you don't have to worry about as mainstream a sound any more, so some bands I would recommend:
Bad Religion, Pennywise, Flogging Molly, Millencollin, Offspring, Sublime, etc.
These bands still have a certain amount of crossover success, but in some cases these groups are less accessible than the recommended 'starters' unless you already have a certain love for punk and/or alternative music.
Next, we step once more backwards, going into the '80s, when we get the more 'new wave' sound going for most punk, but it is still needed to understand a lot of the oldest music. However, depending on the earlier used bands, skipping this step may be advised as many will see it as a 'step back', so to speak, on the lesson in punk.
Talking Heads, Devo, The Cure, Blondie, etc.
NOW, the granddaddies. By this time, they will either appreciate the music or not. These are the standards every punk musician should worship at the idols of, and the list is extensive. I'll stick to three or four examples, though.
Sex Pistols, The Clash, Iggy Pop, Toy Dolls, X, etc.
And, that should pretty well make anybody a convert to punk. Then again, I could make another progression using Folk Punk or Cowpunk to convert those poor souls who listen to country, but I think I'll be flamed enough for the recommendations I've already made.
