Overall I think these logos are some of the best work I've seen thus far - bravo CalligraphyLogo!
That being said, entry 21 is the best I feel. I love the 3D graphic and the INC running sideways like that. I don't know how well it would translate to print or other media, but I love it.
I really like the contrast of entry 5 between words, I recommend incorporating that into 21, perhaps. I do not like the graphic in 5, sadly... too much like A Perfect Circle's last album art, too much like an amorphous snake to me. I think the concept is really solid though - in my opinion, give me some electricity-looking symbols flying through the zero, and now you'd be cooking with some serious fire...
Great designs, keep up the good work.