The third one is definitely the worst of the bunch. You still have the white halo around... that guy... and the textile texture effect is tricky to pull off without looking poor.
You also have some edge issues in the second (your current one) sig. The drop shadow could also be improved, but I can't picture any specific improvements at the moment.
In the first one, I would remove the drop shadow of your name, it looks out of place. And maybe try reducing the noise effect in the drop shadow of the left guy.
As it is, I'd pick the fourth one because it doesn't have any specific errors and it's comedic, which is always a nice change of pace. But if the first and/or second were improved, I'd probably pick them instead.
One last thing: don't be so reliant on filters for your backgrounds and don't be afraid to move away from the archetypal rectangular sig.