User-agent: Googlebot
Disallow:

User-agent: Googlebot-Image
Disallow: /personal
To take another example, say that you want ads on all your pages, but you don't want those pages to appear in Google Search. Here, you'd block Googlebot, but allow Mediapartners-Google, like this:
User-agent: Googlebot
Disallow: /

User-agent: Mediapartners-Google
Disallow: