The chaps over at AnandTech are trying to find out what cards are the best to buy in the mid range market segment:

While this has been quite a lot of information to absorb, we will do our best to sort it all out. Not only is the X1900 GT a better performer in most cases than the stock 7900 GT, but with this week's price cuts the ATI part offers an incredible value advantage. Essentially, this week we are able to get $300 performance for $230. With the recent price cuts (and if you can find one in stock), the X1900 XT has set the (just over) $300 performance mark much higher than the stock 7900 GT is able to reach. They key here is finding a card in stock, as it seems everyone wanted a piece of the action when prices dropped.

Overclocking does help the 7900 GT get closer to the performance of the X1900 XT in some games. If you've got a little extra money, there isn't any reason to buy a product that pushes the envelope of its design just to be nipping at the heels of its closest price competitor in terms of performance. The X1900 XT leads the high end of the midrange market at this point in time, but if your spending limit is set hard at $300 an overclocked 7900 GT that comes in with 550+ core clock speed can be a very good option. With the price difference between the stock 7900 GT and overclocked 7900 GT being just about $15, there is no reason to settle for the significantly slower performer.

On the low end, we've got the stock 7600 GT for just over $160, which offers playable midrange performance at a low price. While the X1600 XT is about $15 cheaper, performance is abysmal. There is no reason anyone should purchase an X1600 XT at this point. With a really tight budget, the 7600 GT offers adequate gaming performance. Overclocked 7600 GT parts are just not worth the price as they don't offer any significant performance gain for the $30 premium. The X1900 GT, however, offers a whole lot more value for the additional $60 over a stock 7600 GT.