100% spray the ceiling BLACK. Do not spray it white. It will always look dirty. Spray black and you will never notice it again. Flat is best, if you get a black tint with a bit of the color from your walls, it will blend better.
If you have water moisture, you can do the raised floor - "DriCore" is what it's called. I used it in my office where I have all our electrical stuff (computer servers, etc) and the rest of the basement is where we had the water issues! Lol.
Get rid of the oil tank - it takes up way more space than it looks, and will cost you $600 for a junk hauler to take it. If they can get it out of your house in one piece, they can re-sell it and you'll have 2-3 guys asking to haul it away.
You're in Connecticut - you will want insulation. There's a cheap way to insulate - using fiber batts (the rolled stuff that comes in those huge bags), but this can contribute to mold if it gets even a LITTLE wet. So better to use Foam boards - the R-value isn't quite as high but you can put them right against the walls, and no mold. You will want insulation if you are putting pins down there.
I wouldn't even worry about the floor unless you have moisture; depends on how livable you want your space to be. My basement is 800 ft2, cost me $21000 to do the whole thing, floor, ceiling, paint, drywall, move the furnace, and we added a bathroom as well.