Lawrence writes:

OK, so say I wanted a rig that would cast a long disance and that were
my only criteria? In the extreme example I might be fishing in the
ocean or on a big lake and casting from shore. Would a longer rod
necesarily cast further than a shorter one? How does the action,
whether light, medium or heavy, affect the maximum casting distance?
What about the other variables? How does the choice of reel, line,
and lure affect casting distance?

I am casting from shore for walleyes on Leech Lake, Minnesota.

Long, long stiff rod, as heavy a lure as you can throw, and as light a
line as won't break are the keys. Spinning reel.

The long rod gives you leverage. Stiffness lets you apply the
leverage well (something springier than a broom handle lets you load
it up and release a bit, but I've never seen anything on the market
that's actually too stiff for your application. A light action will
apply the force too slowly). Finding the optimal lure weight may take
some experimentation, but what you're looking at for distance is
likely to be heavier than you can actually fish once it's in the surf.
You want to be throwing the lure; once it's in the air, pulling line
off the reel just slows it down (and length, heavy lure, and light
line are much more important than the action of the rod). I say a
spinning reel 'cause that's all I know how to cast

A fly fisherman will give you some different parameters, since they
throw the line as well as the lure.