I would think its better to wait and see. Its only around 1 week (or so) wait. Not exactly long. In case iPhone5 has features/specs that you think might suite your needs better, then at least you can wait a while more and get it, instead of looking at your iPhone4 with regret.

You have already waited so long anyway, what is a few more days (or weeks)

Even if you decide not to get the iPhone5, at least the iPhone4 should be cheaper then