I might've already posted a topic like this, but I've rethought my choices. (Getting a cash boost via birthday money doesn't hurt too much either.)

So, I've narrowed down my choices to the 3 listed in the title.
They're all around the same price, so I'm just wondering which will give me the most bang for my buck.

Both the 9800GT and 8800GT are pretty much identical. In my opinion as they both obliterate the 4650 and GT220 which is reflected in all fair tests (benchmarks).

Try not to get a 9800GT GREEN edition, because they have lower clock speeds of around 550mhz instead of 600mhz for a vanilla 9800GT or 700mhz for some factory overclocked versions. They call it "green" because it uses less power and doesn't require a 6 pin PCI-E connector. 

Thanks for the info guys. And one more thing, at my best buy they have a GT 250 on sale for $100, off from its normal $200. Is it worth it to get?

I would hop right on that GTS 250 if I were you. But go onto Newegg or another site and read reviews for the card though to see if it is worth it.