jtowntoflorida,
The save ratio makes the most difference when you use borders. Yes, the crop is different for a 4x6, a 5x7, and an 8x10, but if the important elements of the picture (faces, for example) are near the center of the frame, it probably won't make much difference (relative to not having the pictures at all) when you print in a different ratio. But if you add a border as a 4x6 and then print as a 5x7 (for example), the border draws attention to the edge of the frame. When the ratio is changed, you'll lose more at the top/bottom than the sides (or vice versa) and the crop will be really obvious.