nice idea :) but i think, in terms of relevance, shoooting from a different angle with a shallower dof would have helped :

very relevant, and I love the colour of the cube.
I wish you had chosen a different setting. Red or black velvet would have been nice, and maybe a poker chip...or four poker chips. :)

I think this shot could be improved, I like the diea though. Firstly, a little more DOF wouldn't hurt, the front of the die is out of focus. Secondly, as the subject is four, I'd have put the four on top, as in rolled a four. Thirdly, a different background might work better, making the die jump out at you.

These are just my opinions though. :-)

Since the 6 is up, I interpret this more as Six than Four. That consideration aside, this shot really jumps out at me. I like the contrast of brown table with blue die. I think the image would be stronger with a little more depth of field since the sides of the die are a little soft. This is particularly problematic since presumably for the theme you're trying to emphasize the Four. Also, one minor thing, but a non-casino die would have been better for the image since it wouldn't have the serial number and casino name engraved in the side, which I find distracting.

This was a good spot.. teehee. If the focus had covered the front faces, this would have been better. In fact a few dice showing 4 somewhere would have been very pleasing - why didnt you post sooner, so I could steal your idea :)