I hadn’t asked myself this question – in part because I have one – until reading Norman’s Emotion and design: Attractive things work better. This toaster, shown here, 
dates from the late Nouveau/early Deco period, and as someone who admires classic Art Deco design, wish this type of toaster made it to the late 30s. At half the size of a modern toaster, it is perfect for a small kitchen. It toasts just one side of the bread at a time. Given the popularity of the toasted bagel and English muffin, the design makes perfect sense. The untoasted side of a slice of bread belongs on the inside of a sandwich; it adheres to the ingredients and condiments much better than if toasted. Consider that a slice of bread toasted on two sides has the consistency of shredded (and toasted) paper. Add peanut butter, and you risk choking! However, if you must, once one side is done toasting, flip the bread over.
Each side is angled to give the bread proper rest while toasting. Hence it is an arrow pointing up, a direction in which we all wish to head in the early A.M. when we usually prepare this type of snack.
Modern toasters have settings for bagels. Revert to the old paradigm, and the toaster’s interface becomes much simpler. I’m willing to bet that a poll of people’s toasting habits will show evidence that such a toaster deserves a place in this millennium. Factor in those willing to test my toasted sandwich theory and those numbers may increase.
Modest toaster request: default setting of bagel/English muffin, flip if desired, two door design, maximum 2 buttons, and possibly a color wheel.
I mentioned that I have a toaster like this. I don’t use it anymore. The thought of my bread touching crumbs from the Wilson administration soured my appetite for toast. I don’t eat toast much anymore. I would if I could buy a newer model though!