Good list, Mike. Great thread, too. I'm betting someone will mention an item that each of us either never thought of or have been putting off getting for ourselves (my confession is below

) I would say that you should think ahead with regard to where you are boating when you are limited on storage space-as many of us rolling in bowriders are.
For example, my home lake is relatively small and the lakes that I trailer to within a few hours are ones where I'll be joining people and boating with them all weekend. Therefore, my "tools" that I take on the water on board with me are limited to a cell phone, one of those screwdrivers with the multiple tips stored in the handle, and a medium-sized crescent wrench. If I have a problem that requires more than that I'm either able to call for help, not far from a place I can get help, or I'm boating next to someone who can help me out. Yes, I'm playing the odds based on the fact that my 2007 has 50 hours on it and I'm assuming it is in good shape. But, it keeps me from overloading my storage areas so that I'll have plenty of room for beer and women.
Obviously, boating alone on a large body of water would completely change that.
A few other things:
1. Sufficient sized Danforth anchor and sufficient amount of anchor rode (general rule is 7-10 times the depth of the water where you will be anchoring);
2. Water toys (tubes, rafts, skis, wakeboards, ski/wakeboard ropes & handles, 60'+ rope to pull tubes, etc.)
3. Beach towels, drink coozies, sunscreen, can of wet wipes, roll of paper towels, small container for trash (or a small roll of kitchen bags) and other "creature comforts" (to accommodate food, beer, and women on board)
4. A few hand towels/rags to wipe up spills, dirt, etc. that will bug the $H!T out of you since it is brand new.
5. Paddle, extra prop, proper tools for changing prop. Hey you never know... I don't carry these because I have a Bravo III drive and haven't made it a point to afford a spare set of SS props. Expensive.

Everyone *should* carry an extra prop, especially anyone with a single-prop drive. (I know, I'm a bad boy.)
Check with your dealer to see if they'll be including any of the safety stuff Mike mentioned in his #1. My boat came with a "Coast Guard Package" that included the anchor, rode, fire extinguisher, docking lines, a six pack of Offshore Life Vests.
Even if you don't have your own comfy life jacket to start with, you MUST have a life jacket for every person on board. If you've got any kids coming out with you, check your state rules/regs. In Missouri, any child 7 years or less has to be wearing a life jacket WHENEVER on board-regardless of whether the motor is running or if they are out of the water. Make sure you know the rule for kids in Virginia.
Be prepared to take all of your registration information with you in a Ziploc (waterproof) bag. This is especially true if you won't be licensing it and putting your letters/numbers on the bow right away.
Finally, I'm not familiar with the area you'll be boating in but if there is any chance you'll be in federally controlled waters make sure you are familiar with ALL of the federal rules/regs. I think you said you're new to boating and I think someone recommended you take a course. I wholly agree with that. Even if you can't get out to one somewhere, at least take the online practice test for Virginia at
http://www.boat-ed.com/. It is free, and you can take it 100 times if you'd like. You'd be surprised how much you can learn just by doing that.