<Overkill> So, uh, is it common that trackers actually make samples? Or do they just rip?
<troupe> Rip

There's your answer.

Never track electric guitars. Please.

You can give sample credits in your tunes though. Make the sample names Omni or Necros and people will know you got the sample from a mod by them. Or if you put maz they'll know you got it from a maz pack. Ripping is a-ok though for those of us who don't have hardware to sample!

Actually, to bring another point of view to this, officially and according to law, taking samples from someone else's work without their consent is illegal.

BUT a lot of trackers share sample, and that is their right, too. I've always encouraged sample sharing, and explicitly permitted others to use my samples. I've also known some trackers in the past who held onto their samples like it was a diamond or something and didn't want others to use them. While this kind of person pisses me off, you should respect their right still.

Like I said I encourage sample sharing because I believe that someone's talents come from actually piecing things together and not just the sounds they can bring out of their expensive gear.

When I did my Second Chance '99 soundtrack (my biggest tracking project to date by far), 90% of my samples were ripped. Nowadays, I hardly rip samples because I have a nice hardware synth, but I still encourage sharing.

On a slightly different note, steal one of my melodies and I will hunt you down with a chainsaw :P