I do 2 warmups: 10 reps at 50%, 8 reps at 60%. And one acclimation 3 reps at 90%. This is for most of the lifts. For the heavier stuff, I still do the same warmup but start my acclimation at a
lower weight and do singles until I get to my
working weight.
Doing the full reccomended max ot w/u and acclimation doesn't make the workout take too long though. Remember, there aren't real rest periods between the warmup sets...just do them one after the other until you get your first heavy set done. Then take the 2-3 minutes STR time. If your STR needs longer than 3 minutes, you are probably working too heavy or need a few weeks of cardio to get your oxygen delivery system caught up with your musculature. Remember the bigger the muscles, the more the oxygen demand they need. That's why big muscles tire quicker than small ones...they don't get enough oxygen.
That's why I always suggest cardio and if bulking - eat enough to make up for the extra calories you are burning from it.
Although reccomending and doing aren't always the same thing...I've been a bit of a cardio slacker myself lately. And my squatting and deadlifting are leaving me rather short of breath because of it.