Typically, Cardio prior to strength training is a bad thing. Sucking wind while trying to create tension is a recipe for disaster. Excusing that, you might be tired, or not able to give your all to the lift - thus your effecting you ability to get a decent session in.
Though, perhaps some of you above equate 'puttering around on a treadmill for 5 minutes' cardio. If that, then yeah, depending on how your function, and your goals for the day, it can work.
Personally, if warming up for heavy work, i would typically suggest mega light triples or perhaps 1 set of five (then working to triples), then on to singles, and progressively build. Remembering that your 3-5s SHOULD NOT BE a "Working set". They are to get warm. Not strain you, at all.
Take plenty of rest as required. 10 minutes (or more!) is no uncommon between your 90% plus sets.
Stretching is not a good thing before training. By elongating the muscles, you lower their elastic level, and thus lower strength. The old adage of heaps of stretching before a session is 80s thought. Hell, anyone with practical experience will atest to this. If you want to stretch, Dynamic would be better than static easily. 10 x 2 secs stretches are better than 2 x 10 secs holds.
Now, before people jump at me, i do a 15min warm up routine before i start, but it is not stretching. It is more accurately joint mobility, its to get 'loose'.
*Puts on flame-retardant coat and hood and expects the worst*
- Will