as a fan and collector of the Casio DBC watches, a few years back I decided to make a table with all the differences between the many different models, hoping that others might find it useful too, sometimes!
I posted this on another forum back then, and it still is online over there, but coming here I noticed quite a few people were asking questions about DBC models, not being able to find my original thread. So that's why I'm now posting it here as well. Enjoy!... 

The functional differences are, of course, related to the module being used and not to which one of the many models and/or colour variations it is in, so...

First, a list of all the main models and their modules:

The ones with a B at the end of their model number, are the so called NeoBright ones: they have a keypad with white keys that shine greenish in the dark!
The DBC-61/610/610G with WR on their display, are the only ones that are guaranteed to be Water Resistant (against splashes, but no water pressure).
All cases are made of resin: the Chrome (Gold) ones are of Chrome (Gold) plated resin.
The cases of the DBX-102/112 and DBC-62 are the same and have a kind of rubber keypad.
The DBX-102/103 (Black) and DBX-112 (LightGray) have painted back covers.
Of the DBC-62A, DBM-150 and DBC-81 a version with a yellow display exists.
The DBC-1500B has two (Green 3CJF and White 7CJF) Special Editions with a reversed display (white on black).
(*) And the DBC-63 has a great number of special coloured variations, made in 1997/1998; more about that later on.

As an example I show you the first 8 models in my collection (now containing 12). The pictures are partly mine and partly from others that I don't know (anymore), so if you see yours and would like to be mentioned, just let me know.

DBC-600 . . . . . . . . . . . DBC-610 . . . . . . . . . . . . . . DBM-150 . . . . . DBC-1500L
Click this bar to view the original image of 913x600px.

DBX-103 . . . . . . . . . . . DBC-62-9G . . . . . . . . . . . DBC-63S-9T . . . . . . . DBC-310

But now the functional differences per module:

Click this bar to view the original image of 928x394px.

And finally, as promised, the colour variations of the DBC-63! There are an incredible number of different variations: some are made especially for certain organizations, like the Cognit Schema series for the "Archaeological Institute of America", the Dino Zone series for "The Dinosaur Society", or for Walt Disney. All are rather limited and were only made from March 1997 to February 1998. These keypads with white keys do not have NeoBright. Besides the differences in colour, they also have different pictures visible on the display when the EL Backlight is on.

There are even a few more (DBC-63 as well as DBC-610 and DBC-1500B), made as relation gifts or commemorative editions for mostly Japanese brands or bands. These are not included here, as they are largely the same as the "regular" ones, with just a different brand name and another Backlight picture or display colour.

The information in the picture below is a completed version, based on this website: