Sorry for the additional comment but after doing a little more thinking. I really like the abstract approach to the logo for #68. I don't think the shadow will hold up well in various printing so please remove that. Also, I would love to see a variation of the 4 rectangles in #68 to look like 2 3d rectangles (the yellow would be the left side and the black would be the front.
By the way, my earlier comment I accidently referenced #5. I was actually referring to #68.