I've done back/chest for a few years now. It ends up being a really big day. I only do it once a week. Maybe twice.
I alternate a chest and back movement. Say 3-4 sets of bench and then 3-4 sets of pulldown and so on. Sometimes, I'll superset as well with 6-8 reps of bench with something like 4 pull ups. Ohh, the pain feels soooo good.
It suits me especially when work is busy and I might have to miss a work out.
I also have a legs day and shoulders/arms day.
You can play around with combinations of exercises, intensity, frequency etc to suit yourself.
Mind you, I did fuck up my shoulder while doing all this, although I'm not sure that the two things are connected.