Regardless of how "in" it may be at the moment, I really despise the whole "web 2.0" look of the Sleek Grey one. Same goes for the Dirty and Paper Tape ones.
The Black Aura seems to be the most effective. It is clean, simple and doesn't have all the overdone reflections, bubble-like boxes, and candy-styled buttons look of the majority of the Web 2.0 type sites out there. The other sites all look like a template, so they look like every other site out there. You would want your site to stand out (at least I would) so you shouldn't go for a templated look.