Tarmac,
You might want to check out the scuba board.
http://www.scubaboard.comIts an open forum where you can get varied information about what you want to know about scuba.
As you are in Michigan, you might want to think about how much diving you want to do and what type.
Warm water versus cold diving has just as many fans as AH and WB and the opinions run the same range.
I dove in Hawaii for 9 years and in Puget Sound for the past 3. I like the Sound just as much as Hawaii. Of course I am diving in a Dry Suit here. Its nice to just have to towel off your hair while the wet divers are sprinting to their cars, turing the heater up to afterburner, and trying to warm up.
As others mentioned, getting the right personal gear is the most important thing you can do. I would consider the mask, snorkel, and fins as the basic personal gear, with the other gear being available thru rent until you have more knowledge as to what type of diving you want to do and what brands of products fit your criteria for price, functions, etc. I would guess $75-120 for a good mask, and $130 to $200 for a good pair of fins.
IMO safety rest entirely with you. Its up to the individual to make the determination of whether he can handle the expected conditions of the dive thru their knowledge, training, and abilities.
As Kappa mentioned, the cert is good for life, no renewal.
You do need a cert. You most likely be asked for your card when you rent gear or ask for tank fills, and you cant dive without gear and air.
As far as price of the course you mentioned, it seems reasonable. Call around to some of the dive shops in your area (or even other areas) and do a price comparision. PADI is the largest certifying agency as far as I know but there are others out there that are just as recognized.
Just for future consideration, I have about $700 in warm water gear and about $1600 in cold water. (an overlap of about $300 in dual use gear).
You wont go wrong choosing to dive safe. Best wishes.