The Gringotts Goblins are exclusive to the upcoming LEGO Harry Potter set 10217, Diagon Alley. This will be the second time these goblin minifigures have been available with some differences.
Minifigure Parts and Accessories
Both of the Gingotts Goblins are composed of three parts - head, torso, and short legs.
The heads are light flesh and appear to be the same molds as the original minifigures. Although not shown in the picture, I would expect print to be added to these heads before launch.
The torsos shown here appear to be the same as the one which appeared on the 2010 Professor Flitwick. Again, the prints and or torso colors may change before the official launch.
The legs are the only areas of variation between these two figures. Both goblins are sporting the short leg pieces, but one appears in gray while the other is reddish brown.
Comparing these figures to the reference photo on the right, they are similar to the film versions but not quite right.
Army Building Potential
The ABP for these figures is moderate, mostly for the heads.
Big Draw
I'm guessing we have yet to really see the final variants of these pieces. I'm expecting the torsos to change and print to be added to the heads (similar to what was seen in the 2010 version of Dobby). If print is added to the heads, I would expect the heads to the the big draw here. LEGO Harry Potter collectors will also want an opportunity to have new versions of these minifigures to round out their collections.
(Pictures via FBTB Flickr stream and Harry Potter Wiki)