Entry 1: Bad cutting on Doji, colors don't mix well IMO, and the weird swirls of light don't really fit. Text doesn't go well with the rest of the signature, either.
Entry 2: Not an improvement on entry one at all. Badly cut renders on a simple black background is not very good at all. The text, again, doesn't go with the tag.
Entry 3: This GIF looks like a stock image with some sort of an adjustment, animated, of course. Not a big fan.
Entry 4: I'd say in improvement over the other signatures, but the colors are just really, really off. Ariel 2 is cut odd and the blur on it doesn't help it much either. Text doesn't fit, but it has better placement when compared to the previous tags.
Entry 5: This entry is probably the best out of the group. Only complain is that there's a slight lack of flow and the render doesn't really blend and could have a little bit better placement. Text, once again, doesn't fit, but still a better tag than the rest.
Entry 6: Why'd you put your username on it? It kinda sorta gave away the anonymous feel to the whole GFX Battle. This one looks like 3 blades (btw L-Drago Destroy and Hell Kerbecs still have some white left from their background) slapped on a background with tons and tons of brushes everywhere. Font doesn't go with the tag.
Seeing as my post should have some sort of relevancy to this all, I shall vote for, in order, Entries 5, 4, 6, and 3. But voting for more than one is just pushing it.
EDIT: What Ga' said, hah.