When Do You Add Adsense to a Website?

I recently received an email from a long-time reader who I have spoken with on several occasions and have done business with in the past who is looking for Adsense advice.  He gave me permission to include parts of his email into this post to get opinions from my blog readers:

We finally launched the websites last week (www.FoodBlogs.com and www.MommyBlogs.com).

We’re not in a big hurry to sign advertisers on FoodBlogs.com yet, as traffic is just starting to build.  My developer suggested I put up Adsense (color matched to the site) as an interim solution.  I’ve heard a lot of positives. I’ve also heard that there are negatives to putting up Adsense ads on a newly developed website.

These are fully developed websites targeted to a very large (yet niche) audience.   We intend to develop them further and grow the user-base and traffic to its full potential.  In other words, we’re in it for the long-haul.  Eventually, we will have relationships with direct advertisers or with Ad Networks.
What are your thoughts on Adsense as an interim solution versus something else.

Would you put Adsense on a newly launched site or hold off? If you would hold off, when is a good time to add your Adsense blocks? How do you balance the “stigma” of adding Adsense too quickly with the need to begin generating revenue on an expensive development project?