Wow, some truly amazing shots posted here. I don't even come within the same galaxy of comparison, but since I just baptized a new camera system, I figure I'll play anyway.
The first photos I've ever posted to Wetpixel ... don't be too mean to me!

Goby in a Bottle, Lembeh Strait, Indonesia
Canon 5D in Subal housing, 100mm macro, single Inon Z240 strobe
I was getting ready to ascend from a nice long dive when I saw this little one poke its head out of the neck of the bottle. I dropped down, shot a single frame, and got lucky with the focus and strobe positioning.

Coleman Shrimp, Lembeh Strait, Indonesia
Canon 5D in Subal housing, 100mm macro, single Inon Z240 strobe
It was my last dive in the Strait, and we were looking for harlequin shrimp. Instead the dive guide banged his tank and pointed these out to me. Silly me, I was disappointed because they weren't harlequin shrimp, but now I'm glad I stayed with them as long as I did!

Bearded Fireworm on a Sponge, Cozumel, Mexico
Canon 5D in Subal housing, 50mm macro, Inon Z240 and D180 strobes
With lots of particulate matter in the water column and severely reduced viz, we weren't having much luck spotting anything on this dive, so when I saw the bearded fireworm, I decided to spend some time with it. It's not an unusual creature, but I like how the image turned out graphically.