In my short time as a collector, I've discovered that for a watch to remain in my collection, it needs to be legible at a glance. I'm the kind of guy who doesn't like having to take more than a second to read the time: pull back sleeve, glance at watch, release sleeve -- one smooth motion.
As I was browsing for my next keeper, I came across the Sinn 556. The watch seemed perfect for my 6.5" wrists: 38.5 mm case diameter, low profile, etc. One problem. The hour markers are all identical. I looked at several pictures and I feel dumb for admitting this, but I'm certain I wouldn't be able to tell time with this watch at a glance despite its stark, legible dial.
(courtesy of feng)
So, I'm opting for its brother instead even though I prefer the cleaner look of the first example.
So, what are your favorite at-a-glance pieces, preferably ones that you've owned?