What are the pros and cons of different types of shifter cables?
Regular cables:

Pros:


inexpensive
easy to find


cons:


generally lower quality than slick ones
much of the time they are not pre-stretched, so they have to wear in.
heavier 


Slick cables:

Pros:


initially slightly faster shifting
generally come pre-stretched
lighter


cons:


(a big one) once the coating wears off, the shifting becomes A LOT worse, and the cables need to be changed. This is fairly common if the housing isn't cut right or there is bend when entering/exiting a housing stop. 
very expensive 
installation is harder as the cables are more fragile
adjustment is more finicky 


Stainless Steel Cables:


don't rust
slightly slicker


Galvanized:


Cheaper
more bendy