I do 5 - 10 minutes of Foam Rolling (soft tissue work). I static stretch my hip flexors & IT Band pre work out, 95% of the time anyway. I also static stretch my upper traps pre work out, most of the time. And I always do up to 5-10 minutes of dynamic stretching, pre work out :-)
I'm a 'desk jockey', therefore, I need to static stretch these muscles constantly, sometimes i stretch my hip flexors between exercises. I also do some dynamic movements for my calfs and ankles between exercises, sometimes anyway.
I have 2 warm up routines that i alternate between - to suit my upper body and lower body days. Hence some stretching I say is "most of the time". I also train in 4 week cycles, again, hence the "some times stretch this or that". My warm up, including foam rolling probably takes 15 minutes depending on how stiff or balled up things are.
Post work out, I knock back a shake and curl up in ball for a while (on my leg days anyway) :-)
Highly recommend dynamic warm ups. And, if i wasn't battling with imbalances, i wouldn't static stretch at all pre work out.