A word should be said about ATI's new x1800XL card, ATI's answer to the 7800GT. ATI launched the R5xx architecture early last week. They feature Shader Model 3.0, angle-independent Anisotropic Filtering, adaptive antialiasing and the ability to do HDR with AA at the same time in games. From the previews that have hit the net, the 7800GT has an edge with performance in most cases. On the other hand, ATI's cards are only now hitting the store shelves.
I never recommend a card I've never had experience with. NVIDIA's card is out at multiple locations around the net. ATI's is just hitting retail markets in the last week and we should be getting in one to review soon. At this moment I would recommend the 7800GT. Once I get experience with the x1800XL or x1800XT I may change my mind, but as the x1800xl is $100 more online than the 7800GT, the choice is pretty clear.
GIGABYTE brings to the table a solid gaming bundle, good performance, and their good reputation with their 7800GT card. Other cards are on the market with higher clocks, like the eVGA 7800GT CO or the XFX 7800GT. At the end of the day, I would have to defer to XFX's or eVGA's cards, as they come overclocked out of the box and offer a Lifetime warranty. If GIGABYTE offered the same warranty and an overclocked version of the card, the choice might be their card.