Two years ago, ATI lost the crown in their desktop GPU to Nvidia when Nvidia launched their Gforce 6000 series and then followed by the 7000 series GPU.Since then, ATI was not able to match the power consumption and the performance of those cards. Since last year, ATI has taken back some of the lost glory of Nvidia through HD 3800 series. Those cards are not spectacular and could not match Nvidia's 8000 series GPU but nevertheless, price and performance wise, they can match Nvidia.
Nvidia produced many GPUs for both desktop and notebooks. Their famous GPU for notebook would be the 8400 series or 8600 series up to the very high end 8800M .Recently, they have released the 9000 series GPU for laptops. You can find it in Alienware, Rock and also on Dell laptops. They even featured on SLI configuration. I can just imagine the power consumption using high end GPUs as a waste of money. If you don't really play graphic intensive games or studio work, I don't think it is necessary for you to buy high end graphics card. I don't do it anyway. My pc's graphics card is a Gigabyte Silent 8600GT with 512MB with GDDR3.It is not a high end graphics card but it is sufficient for me. It is cheap at around £50 and good for my waller. Do you really need a Gforce 8800GT? I do know that the performance is good but power consumption is relatively high with Gforce 8800 and ATI HD3870 and above. Think about reduction in power consumption.
We have been talking about saving electricity. Newer graphics card by ATI and also Nvidia got to use a lot of electricity hence the problem of increased in electricity consumption of many households. If you have deep pockets, Nvidia's 8800GTX Ultra or the ATI HD 4870 will be sufficient.Presently, it looks like ATI is gaining a lot of ground compared to Nvidia and this is a battle which has no end. It is also good for consumer as in choices.