HD4650 or 9800GT

Yeah, you'll want a GTS 250 or HD4770/4850 for that resolution. Any of them are much better than an HD4650.

An HD5770 isn't too bad either.

So what difference will I notice with the new Physx option???
Also, will my 460W supply be able to supply the juice???

Your PSU is a pretty good brand and should be fine for these cards.
And yeah, an HD5770 is good. It's also $50-60 dollars more expensive than the other cards.
I wouldn't worry about Phys-x. It's not used in that many games and when it has been used it doesn't really add too much.

Check out ebay. People put video cards up there all the time (I buy a lot of graphics cards on ebay - very few have any issues at all)

But the Geforce 9800GT is a good card and the GTX250 is better...
I am a big Nvidia fan myself, but if you are on THAT much of a budget... look into some ATI boards...

If you are willing to fork out extra moneys.... definitely go with the GTX 275/285.

For that resolution 9800GT won't be enough will all the eye candy(I have that card).
So go for GTS 250 or HD 4850.

Overclock your CPU for better performance.

BTW what is your Budget?

Would say that GTS250 is the best option that i can think of, looks like you are inclined towards PhysX. Otherwise HD5770 is a wise choice.

Performance at x resolution is BS - doom 3 will run at a high res at max on any card these days yet newer games wont as a great example so why are people always asking what card is best at x res? 100% BS

Get the best card you can get at your budget - its the only way.

If you can afford to get a 5970 get it, otherwise go for something cheaper etc - its that simple.

Doom 3 came out over 5 years ago... What does it have to do with anything? It can safely be assumed that most people aren't looking to buy a card these days to play Doom 3. Just look at the OP. I'm sure it's little consolation to the guy that the HD4650 he purchased can play Half Life 2 beautifully at his resolution. Similarly in a few years now no one will care if a $50 card can play GTA IV or MW2 maxed out at high resolutions. They will care about if a GTS 450(which is really just a renamed GTX 385   ) can handle Bioshock 3 or Resident Evil 7.
To run games at higher resolutions you need a more powerful card. It's simple, higher resolutions = more pixels = more graphical power required. There's no BS involved. I'm not exactly sure what you don't understand but that you needed to bring up a 5 year old game no one plays any more to make a point should give you pause.

Ok thanks alot everyone for the invaluable advice. Will go for the GTS 250 after all. I know ATI cards offer more bang for the buck at this price range but personally, I like Nvidia hardware.

Once again THANKS!!!

I'm going to agree, overclocking the CPU should help considerably and that 6300 should have a lot of headroom. I run a 2180 at 3.0ghz with a 4850 and I get very good framerates on all the games I play. (Wow, MW2, L4D2)