How much time do you dedicate to strengh training?

I normally just do a couple of hours a week, in two sessions.

Monday I do heavy chest and back exercises, alternating between the two, with maybe 30 - 60 seconds between exercises. I then do some additional shoulder and arm work at the end. Normally around 12 sets for back and chest, and 6 or 7 for shoulders sees me done. This takes about 70 minutes or so.

On Friday, I do a more metabolic conditioning workout - higher reps, virtually no rest, more dynamic, whole body movements. I've also tried a killer triset routine where I'll do a set of heavy back for 8-12 reps, then go straight to heavy chest for 8 - 12 reps before doing heavy shoulders for 8 - 12 reps. 50 seconds rest then repeat again for a total of 12 trisets. Only takes 40 minutes or so, my heart rate is at spinning levels, and, surprisingly, I can pretty much shift the same weights for the same reps as I do on the Monday workout (it is Hellishly hard, though, so much so that I sometimes can't face it).

And that's it for weights. Everything else is either mountain biking, spinning, Yoga or Plyometrics / Insanity.

Then again, that's my weird ol' system.

You have a variety of choices with weights, though.

But what you do depends on your goals. Do you want to get bigger or stronger? Or both? Do you want to use weights to get better at a sport/activity or do you want to use weights as an alternative form of cardio?

Your goals will dictate whether you train the whole body or split it into body parts. Whether you use high reps or low reps, machines, free weights or body weight.

Without knowing your goals the only sure thing that can be said is make sure you get enough rest between weight workouts - you don't want to be hitting the same bits of the body two days on the trot.