I love weight training. Not as much as IMA, but I make it a part of my training.
The method which I do is geared for strength, rather than excessive size. When you start to life heavy weight, some size naturally happens and that is a byproduct. So in that regard, I'll do single reps of something heavy or something like Pavel's Power to the People routine, which is some variation of a couple sets of a few reps.
That's the how, the what is:
dead lifts
squats
clean and press
bent press
that's mainly it, but that's plenty.
I'll also use the kettlebells for the clean and press and also for the endurance work of the swings and the snatches.
On the other side of the spectrum (but still not in the zombie bodybuilder gym guy zone), I've done a very watered down version of the 20 rep squat routine, just to try it. It works, it puts on size and strength. I'd like to do it for real just to see if I have the mental strength to go through the thing but like the experts say, you'll need some cash to buy new clothes.
As for your internal development, well, I've got a long way to go in continuing the IMA but I don't see how it will destroy your chi. It's a myth. That is unless you become a zombie gym guy who just does curls all day.
When it comes to flexibility, it is still important to stretch. No way around that one. Even without weight training. So it becomes all the more important to keep up on it with weights. Still though, if you are focusing keeping the reps low and the kilos high, then you will get very strong and won't have the flexibility of this guy: