Dave, I think some of my work might be pushing the envelope in terms of high resolution images from film. I shoot 8x10" originals and scan them at 2000 dpi (contrary to popular belief, using higher resolution doesn't provide any additional image information, just more grain), and that process produces files almost a gigabyte in size that have image details as small as one pixel. A few of my images are multiple 8x10's laced together; I have a couple of panoramic images that are composites of four 8x10's in a row-- the equivalent of an 8x40" film original. They are a nightmare to lace together in Photoshop, but the resulting prints have more detail than our eyes could see if we were there in person.
However, I think there is a limit to how useful that much image information can be; for my own work it matters because my images are all about small details, but for other kinds of work, too much information can actually reduce the emotional effect of the image. I've seen some very high resolution landscape photos recently, whose only interest is their extreme sharpness. My own reaction to a lot of that kind of work is, "amazingly sharp, but so what?"