#25: I like the concept but if you could please consider the corporate aspect of our company when selecting the background color. I think a slight modification would pay huge dividends. Also, our company creates LED Light Lamps, the "D" is too reminiscent of an Edison based incandescent, which this industry is replacing.
#44 : I like this "D" and the one in #43 much better. If this could somehow be fused with entry #25 while adding a more corporate shade of blue to go with the White and the Green it would be really strong.