In recent memory CRX’s 18500 shorty jumps out in my mind in a practicality/feature rich sense. I hope he doesn’t mind me linking his mod here. At the very least I won’t steal one of his pictures & post it up.
In terms of pure visual eye candy their have been tons(CRX of course has made a few of these gems too.)
EDIT - & FYI I was the winner of WillyD’s beauty. Despite owning more than a few lights that light lives in the flashlight carrier of my Maxpedition Fatboy bag that I only take out periodically during nighttime. It serves it’s role awesomely because that light is always visible at night no matter what I’m fumbling around with. Being a tube light it was never intended to throw greatly but so far it gives very decent illumination on whatever I needed it light up. In my mind it’s the perfect tube light to live in that tube holster of my nighttime bag. Thanks again WillyD!