Are there some general rules of thumb for the various types of rods one should use for various applicatioins?

What kind of rod (medium, medium/heavy, etc.) and how long would one use as a "general" rule of thumb for plastic worms, crank baits, spinner baits, jigs, etc.

I got to wondering about this after seeing the thread on top water rods.

I only have a few rods right now and as I look to expand in the future, I'm trying to get an idea of what I should be aiming for when I make my next purchase.

I realize I may get several different answers here, but any input would be greatly appreciated, just the same.