Which Google AdSense services to use?

I have Google AdSense.

Should I use put Google content ads, Google search box, or Google referrals on my site?

I know you are going to say put all three. But I have limited space for ads on my site and I am wondering which of the three is most profitable?

content ads.

Use the search box only if you have a site search you want to monetize. Use the referrals only if you run a tech or webmaster site.