With regard to Spinning (I took a couple classes - it kicked my butt!) and compound exercises, I think that ANY activity which makes you more fit, may help your golf. One proviso is that you must maintain your flexibility.
If I were to perform "traditional" exercises, I suppose squats and deadlifts would be more beneficial than any number of the dreaded "machine" based exercises such as leg press, hamstring curls, or knee extensions. (Of course, your back may not like them in the long run, but that's another story...)
I still maintain that at least some of your golf-specific exercise should look an awful lot like golf. It should train the body to rotate, should include some speed activities, should train golf posture/address, should train maintaining the spine angle, should work on balance, etc. Of course, it would be nice if you could get all that in a limited amount of exercises(Instead of having one for strength, one for speed, one for posture, etc.)
It also would be nice if the exercises actually ingrained proper swing mechanics.
I think that any exercise program would benefit from including a cardiovascular component, from a general health standpoint if nothing else.
Not sure spinning will do a whole lot specifically for golf, unless your legs are significantly deconditioned.
Edit - oh yes, I agree - a very fine golf fitness forum. I just wish there was a LITTLE more activity.
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