Re: Resting between Reps - when its considered a set vs. heavy singles?
Between deadlifts, I routinely let go of the bar and stand up. Every rep I re-check my foot position, descend to the bar and grip it and stand back up. I only consider the set over if I deliberately rest (i.e. I'm not setting up for the next rep, I'm waiting to recover). This usually means my maximum 5 rep rep sets take about 30 seconds or so. Since I'm rest 5 minutes between sets, a few seconds between reps is peanuts. 5 Singles to me would be taking a full rest (again, for me it's 5 minutes) between reps. The important thing to me is de-weighting the deadlift and ensuring a proper setup and good pull...not rushing to the next rep.
For things like the bench press, yeah, racking ends the set for me. Same with other exercises if I put the bar down. But for "dead weight" lifting putting the bar down is part of good technique for me.