So in the old days (2 years ago) you could have a 5D like mine and then upgrade an XTi to a 30D for backup. One of the advantages of this is that these cameras use the same battery.
Since its always good to have extra batteries its not uncommon, in this example, to have three to five batteries. So along comes the 5D MII, 7D and now the 60D.
If you have two cameras, you are almost forced to upgrade both. Some may have done that, but then again maybe you upgraded just one of them and you live with two battery types.
So the question is does battery type affect your purchase decisions?
but I'm the type who will always include a grip with my camera purchase...
