APL triple-shot beam spring keycaps • Oooh, what's that you have there? A beam spring keyboard? Sure, the best of the best, but did you get it connected? Oh, you did. But what's that? Triple-shot keycaps? OMG DO WANT!
Original Cherry dye-sub PBT keycaps • Nothing beats the original! Thick, mean and strong plastic, these caps don't wear and don't get shiny as fast as other keycaps.
Retro DSA keycaps • Many people got great retro DSA keycaps thanks to matt3o's group buy. Finally you can transform your modern keyboard into a Commodore 64.
Round 4 spherical keycaps • 7bit's enormous Round 4 group buy was completed, resulting in lots and lots of keyboard porn.
Topre's HiPro keycaps • The Realforce HiPro ("High-Profile") is a full-size keyboard available in a couple of layouts, sporting high-quality Topre switches and spherical keycaps.
And the Wingnut for Best keycaps 2013, as voted for by the members of deskthority, goes to...