The first thing to consider when youre shopping for an AIO is which functions you need. The lowest price models are usually limited to printing, scanning, and copying, but there are lots of other possibilities.
The most important other functions are faxing and e-mailing. Some AIOs can also scan film (slides and negatives) by way of a transparency adaptor in the scanner lid.
A few high-price home AIOs double as standalone photo labs to let you print high-quality photos from memory cards, PictBridge-enabled cameras, photographic prints, and transparencies--most often 35mm slides and negatives. Some also let you print directly from other sources, like USB keys.
These photo lab AIOs (for lack of a better term) typically offer a reasonably large color LCD--often 3.5 inches--for previewing photos before printing, and they pair it with an array of buttons and a photo kiosk style menu.
One thing to remember: If you already have a fax software and a fax modem in your PC, you can generally count on using that to control the AIOs scanner, so you can scan and fax, even if the AIO itself cant.