I don’t print photos very often. I’m happy keeping them digital. Still, a cheap color inkjet produces some great prints when you want them.
Windows 7 has a built-in Print Pictures function that opens a dialog box full of options. One option in particular gives me pause: [x] Fit picture to frame. Fit – as in make it fit? As in: if the photo is too big for the frame (print area), squeeze it to make it fit? Well, no. See these two examples.
In the first figure, the Fit option is checked, as it is by default. The photo fills the available print space. Only the birds on the left and right hint at a problem.

The second figure shows the full picture because Fit is unchecked. In order to fit the true width of the picture, some print space is left blank above and below.

One might argue the problem is the cropping of this photo, but it is cropped just the way I want it and I think that cropping works particularly well onscreen. And what of panoramas? To me, the problem is the word “fit.”
My advice: When cropping, keep printing in mind if you intend to print the cropped photo. When printing, preview each print with and without this option checked – it makes little difference for photos whose aspect ratio (height to width) is close to the aspect ratio of the print area, but the difference may be significant.
PS: This isn’t just a problem with printing cropped photos. Most film had an aspect ratio of 3:2 (making a 6×4 print). Digital cameras picked up TV’s pre-digital aspect ratio 4:3. Some cameras shoot the HD (from movie) ratio of 16:9. So, getting a photo to look great on a computer screen, on TV, in a digital frame, and in print is, well, a challenge.