An old Australian told me, "you don't need it, just go." He was
actually talking about equipment but equipment costs money. You really
don't need as much as West Marine implies that you do.
You do need an accurate voltage gauge to monitor your batteries but if
you do some research (Trojan is a good site to start with) you'll find
that you can get along perfectly well with a auto battery charger. If
your solar panels and/or wind generator don't get your batteries over
13.5 volts then you don't need a regulator for them since 13.5 is
about what an expensive three stage battery charger will hold your
batteries at anyway.
I could go on and on but the secret is to research the system until
you really do understand it and then buy what you need.