Basically, my example of that bach piece is not the best example, because the basic counterpoint stuff is about 2 melodies playing together with 2 melodical lines. In my example, you can hear a lot of different lines coming one after the other, each one leaving some sort of strong influence on the next melody. The next phrase sits over what brought the precedent one. It's not technically "rigourous (or straight?) counterpoint" (dunno how it is said in english, in frenche "contrepoint rigoureux").
For smy1 :
I think the first sentence of the wikipedia article is well written :
"In its most general aspect, counterpoint involves the writing of musical lines that sound very different and move independently from each other but sound harmonious when played simultaneously."
The term comes from the origins. At first, religious songs were not melodical (I'm not even sure melody did exist as we know it) and with the time, there was first the idea to double the sound with a 5th (which is still not another melody, it powerize the original one, like a powerchord), and with the time came the idea to create a melody, and another one that was getting lower when the first got higher. As the music notation was just created with the invention of melody and timing, written with "points", it was named "counterpoint". Basically, it means "creating harmony with independant lines".
(sorry if I say something stupid, I'm not a pro)
It's a bit creating music horizontally, whereas the harmony approach (a succession of chords creating a melody uppon itself) is vertical.
About chugga E rythm, technically, it may be what is called a "bourdon" (dunno if the term is english too). It's a note that never changes and emphasizes the whole harmony.
And yes you need melodies for counterpoint. Basically you can distinguish 2 things : melody and harmony. A melody is a melody, and harmony is about chords. You cannot create one without the other, but you can play with them. For example, in my video, a melody makes you hear chords, and when you play a succession of chords, your ear automatically hears a melody. I don't know if this melody is theorically predictible, I guess yes, but I have a poor music theory knowledge so I'm not sure.
Basically, when you write 2 lines, 1 for each guitarist, that are both melodies, and that interact together independently, it's counterpoint.
I guess when you write harmonized guitars ala In Flames, it's harmonic, because they create chords a dependant manner.