Ad Placement Based on Site Membership

Is there any logic behind showing/hiding advertisements based on whether a user is a member of your site? I had someone design a new user interface for me, and I thought the ad placement may be a bit too aggressive. Initially there was an ad right under my banner, but I chose to remove it for now.

Would it make sense to show this ad only to visitors and hide it for existing members? I guess the trade-off is that visitors who are potential members may be turned-off by the aggressive placment of ads and never register at all.

Not showing the ads, or so many ads could be used as an incentive for people to sign up, or you could make it part of a premium account.

Other than that I would just keep it the same for both, I don’t see much point in segmenting this way.