I seemed to have his a nice routine that works well for me:

Warmup:
Stretching
10-15 mins on treadmill, slightly above walking pace, but at a good angle. I 'push' into the handle bars so that it really gets the blood going.

Lifting:
Depending on the muscles being worked, I'll warm them up with a few light weight sets. For example, if I'm doing chest and back, I'll bench just the bar for 30-40 reps, and then add about 20 lbs for the other sets. Then I'll do rows with little weight like with the benching.
After that, I'll roll into the heavier weight.

I've tried 5/3/1 but GODDAMN it burnt me out fast.
I like doing a 12/10/8 rep setup and get wicked pumps doing it. I go up much more slowly in weight, but the muscle is much more dense.

If I'm on a cycle and trying to get bigger/stronger, I've found 5x5 sets work very well.

I always love to mix it up though. Running 12/10/8 for a while and then throw a 5/5/5 in there with much higher weight really feels good.