There was a post to this affect some time ago, more about noise-noise:
viewtopic.php?f=62&t=332547&start=30
Certainly, things like low end hum are annoying. But the drive to reduce all noise from decks / tape machines and final production since the mid-70s means that if you want to sound more authentically 60s / early 70s, you may want to introduce some back in, depending on the effect you want.
Some deck channel emulators of course go as far as introducing some cross-talk (which you can do manually), but a very gentle white noise hiss will fill in frequencies and eliminate the "dead silence" during gaps. You could even add some vinyl scratch to be super-authentic (assuming you're never going to mix the track to vinyl, then it's redundant).
Layering the kick with a very, very subtle rattle / snare is a cool effect when triggered sparingly (with velocity). Some drum instruments have a separate mix for snare bleed into the kick.
Really though, I like the little room sounds, vocal whoops. Look at a lot of Pro Tools sessions and you'll see the vocals clips are silent when there's no vocals. Now listen to this (one of may favorite tracks for that "we're all playing in the room" sound). Jagger's mic is on the whole time, and he can't quite shut up during the solo at 2:10. That's some rock magic right there, which you never here in a "modern" mix
Make some noise, let it bleed into your mix! (Let it Bleed - lol, see what I did there, Stones?)
https://www.youtube.com/watch?v=a4g8PxsG_j4
