There are questions I have asked myself, and these are the conclusions I have come to for the sort of photography I like to do. Take them for what they are. Think for your self.
Never mind buying extra fast Compact Flash Cards. As an experiment, I held the shutter button down on my EOS 20D and counted the frames till the internal memory was full and the Card became the limiting factor. That was at 40 frames, after which it still kept going more than adequately. My conclusion is the cheapest cards are more than adequate. Of course, the number of frames will change greatly according to ambient light settings, as well as shutter speed-aperture settings, ISO etc. It's up to you, and the sort of photography you like.
Never mind buying the camera body batteries from your local shop; genuine or compatible battery versions. These are about £50 (UK) each. I found the look-a-like versions from 7DayShop.com worked perfectly, and at only £5 (UK) each, were a bargain. Yes, that's only 10% of the price. I've had mine about a year now, and they are still working fine. The decision is yours!
A friend of mine has gathered his favourite photographs and published them as a book. He uses Lulu.com. Of all the on-line companies I have read about or seen for making hardcopy books from your photographs, this one, for me, is the best. Why?