Take a deep breath... we've all been there, and we're all still tweaking our systems. The main priority right now is to get it into a state that you'll use, and that generally means short and sweet.
If I was starting a fresh system now, this is what I'd do:
1. Make a list of your Areas of Focus or responsibility. Those are the "hats" you wear, and all of your projects will fall under an area of focus, so it'll help with organizing. For example, at work, you might be responsible for Programming, Marketing, etc., and at home you might be husband, child's father, home owner, car owner, photographer, guitar player, etc.
2. In OmniFocus, I have 4 folders - Home, Work, Home Someday Maybe, and Work Someday Maybe - and the projects go within those 4 folders. I start all my project names with the area of focus - it just saves ending up with hundreds of folders. Try moving all your newly created projects into the 2 someday maybe folders for now, and right-click to put them on hold. You'll feel better!
3. Your mindsweep's great. Try thinking about what the end result is supposed to be for each action. For example, buy white paint might be the next action in a project called Home - Decorate Office.
4. How many of those projects are you expecting to move forward in the next week or two? Move them out of Someday Maybe folders into the active folders. Make sure they've all got sensible contexts. Having a nice short 'doable' list of next actions will make you more inclined to use your lists. There are odd longer term ones that I'd make active, like the Decorate Office, just because I don't go to the DIY store every week and I want that action available.
5. Make sure you do a weekly review within the next week - you might move some additional projects into the active folder, and move some back to Someday Maybe. That's fine. Get into the habit of doing the review as regularly as possible, and keep the lists short - that'll build the trust and remove the wobbly feeling. Read your active tasks lists in the morning - that'll help too.
6. Keep adding stuff as it comes to mind, but remember, just because you've had the thought doesn't mean you have to put it on active lists yet. Someday Maybe is your friend as long as you review it regularly. You'll overwhelm yourself if you start trying to move all your goals forward at once.
7. Sign up for the 2 week trial of GTD Connect (or sign up long term is even better!). There's some real gems in the webinars, and some great getting started guides in the document library, including a getting started guide for omnifocus and a more general implementation guide which would really help.