Good gpu manufacturer

They are all good. I mean none of them really make the GPU, NVIDIA does. They don't even make the cards themselves, with the exception of a few "special models". They just slap their sticker on it and flash the BIOS with their info. You are basically paying for the companies support and any additions they made to the card.

Gigabyte has an OCed model out with a nice cooler on it. A buddy actually just ordered one of these for a build. http://www.newegg.com/Product/Product.aspx?Item=N82E168...
I have been a fan of Asus as they always unlock the voltages so you can tweak them.
Just look at the prices and see what there is. Don't pay to much for one just because of the brand and look for deals. Although these cards are new so there will be few deals.

Yes, Nvidia and ATI give them their chips, then they just put them in their boards and/or heatsinks.

Gigabyte, ASUS, EVGA, MSI, XFX, they're all very good.