What do you think the most underrated "common" fish is?

Not a fish, but I'm going to say Mystery Snails/Briggs. I love watching them scoot around my tank. As far as fish goes, one that I have always loved but rarely read about is Emperor Tetras. I find them so very pretty.
 
Giant Danios - lots of neat colors if the slow down long enough for you to get a good look at them.
 
Oh and one other is the Tetra Minor, unappreciated for its ability its hardiness and tank mate with almost any fish.

The head Fish lady at PetStart was telling me that almost all of their original Tetra Minors when they opened the store last December are still alive.

I have had they as tank mates in my 244 tanks with 19 Mbuna's and they they get along amazingly well. But most people don't buy them becasue they do fin nip weak or over docile fish.
 
Harlequin Rasboras and Praecox Rainbows.......
 
I have to add zebra danios. I have had mine since I cycled the tank, and they are really interesting to watch interact with eachother -- they play "leapfrog" in the current of my filter!
 
I agree about the albino cories. Everyone I know has peppereds, or pandas, or sterbais.

Also- ember tetras. They haven't even been mentioned yet! I just bought a bunch from a LFS. They had a whole tank full, and the guy working there said he was taking some home the next day, that they were great fish, but they had barely sold any. They're small so I got a whole bunch, and they're pretty tight schoolers- fascinating to watch!
 
AquariaCentral.com