I want to get the 40D eventually or even the successor (50D?) in the future. The 40D is 10MP camera, shooting up to 6.5 FPS. So, what is the bare minimum MB/sec I should get for a 40D? I dont want to get a incredibly fast card if I dont need it. Ex: 30MB/sec Also, is that megabytes a second or megabits a second?