ok....however..r the drivers for the 5xxx series working well as compared to the nvidia....and bear in mind please..lol..im just starting ti learn this stuff..lol..my 4850 seems to struggle and have problems with the new 10.5 drivers,,so i rolled back to the 10.4..and its stable again..but i am thinking the nvidia drivers r alot more stable..am i wrong?...
You might want to consider the 5770. Not a huge upgrade from your 4850, but it is faster and can be found around $135. This saves you $60+, and its not much slower then the 5830.
There are no cards in this price range from Nvidia right now. The GTX2xx series isn't worth it, and there are no GTX4xx series cards in the $200 price range yet. Even the GTX265 is a bad idea as its about the speed of the 5830, but with the 5850 price tag. You can try waiting, but it will probably be awhile before Nvidia can get something down in the lower ranges.
I'm running 2 Sapphire 4850's OC @ 1920x1080p via HDMI to my LG 47LG70 (47" 1080p LCDTV) and I can run all games on the highest maxed out settings and they run flawlessly. Crysis on very high @ 2x AA gets me 45+FPS. Modern Warfare 2 on very high settings @ 4x AA gets me 90+FPS. Battlefield Bad Company 2 @ Very High 4x AA 16x AF gets me 60+FPS. A friend of mine just built a rig using 2 Galaxy GTS 250 in SLI (which was $100 more than my 4850's ;] ) and he can't get anywhere near the frame rates i do @ 1080p. Hope this helps ;]