Doc's suggestion of a DSLR is a good one, because of the flexibility interchangeable lenses will give you. As far as bodies go, pretty much anything from a major manufacturer is going to be equally good - in terms of picture quality, there's no real difference between a Canon, Pentax, Nikon, Olympus, or whatever. Most photographers choose a brand more for its interface and ergonomics than for its features, since they're all more or less comparable at any given price point. (And they all offer the option of including the file name in the image, as far as I know.)
More important is the lens. You can get a good macro lens new for a couple hundred bucks. If you need a cheaper option, scrounge your local camera shop for something used (my go-to macro lens was $5 in a junk bin). There are also extension tubes you can buy that (supposedly) turn any lens into a macro. I haven't tried them myself, but I've heard good things.
Another option is to stick with a basic lens and go for broke on resolution. A 14MP image taken from a foot away (which should be within the ability of just about any non-telephoto lens) is going to be extremely detailed. You can also back off a bit and zoom in - many lenses have an easier time focusing that way. It will increase your depth of field, but probably not enough to be a problem. (These will both work with a point-and-shoot, too.)
In the end, just about any decent camera will do the job, as long as you know how to use it.