What's a decent CF card for Nikon D3?

I have recently upgraded from a Nikon D300 to a D3. I was wondering what sort of CF cards I should get, so I can get speedy performance without breaking the bank.
I currently have a few 4gb Sandisk Ultra II's (15mb/s), though I doubt these are up to it. I'm not sure how big the D3 buffer is, off hand.

I do a lot of birding, so I usually use a fast frame rate. 6-8 fps.

Since you will not be using your D3 for shooting video, ANY brand 266x CF card will keep up with your shooting rate. Just buy about 7 - 4 gb cards and carry one in your camera and the other six in a card case.

My friends who are birders rarely machine gun their birds.

The know the behavior of the birds they track, count and photograph, so the use shot discipline to photograph the birds the way most photographers do when shooting action. They anticipate the behavior and take one or two shots in the single shot mode.

While Ace has given some good advice, sometimes is is necessary to use burst mode (especially since I do animated images).

The way I look at it is, why bother with different speed cards! I just buy/use cards that I know can handle what I throw at it when it is needed. That way there's no guessing what card is in the camera and where the faster cards are at.

I prefer to use 45Mb/s CF cards from Sandisk (Extreme IV), Kingston, or Dane Electric