This card is the best bang for the buck right now, period. The X1900 GT will even beat the more expensive 7900 GS. The only reason I've included the more expensive price segment below is because I'm not sure how long these X1900 GTs will hold up in retail. I believe they are no longer making them anymore, but they are an amazing deal.

The X1900 GT is based on the X1900 XT core, only stripped down a bit - some pixel shaders are disabled, and the card is clocked slower than its XT cousin. There are now two versions: the original 575 MHz core / 600 MHz memory card, and the new 512 MHz core / 6600 MHz memory version. Both perform similarly.

Best PCI-E Card For ~£150 / €200: Tie

This card is essentially an overclocked 7800 GT; sporting a 256-bit memory bus and decent clock speeds, it's a very good performer and a solid card for the money.

While the X1950 PRO is a stronger performer, it's also a bit more expensive. The 7900 GS also has a good overclocking reputation, unlike the X1950 PRO.

The X1950 PRO is similar to the X1900 GT, the main difference being that it is not based on the X1900 XT, but rather a new, less power-hungry core. The card's main competition is the 7900 GS, which the X1950 PRO will beat in most benchmarks at stock speeds. However, the 7900 GS tends to be cheaper, and the X1950 PRO does not overclock well, so they are both good buys depending on how you plan to use them.