Is there a way to NOT share gaming statistics with friends on Steam?

You can make your profile fully private, following these instructions:

1. Log into your Steam Community Profile
2. Click the Edit my SteamID page link
3. Click the Settings link
4. Choose your privacy state
5. Click the Save button

However, it hides away all the profile, not only the gaming history.

Steam has changed since 2010 so here is the updated 2018 answer

Yes, you can hide your personal stats. Per the blog post made in April of this year you can hide your "hours played" and manage what you share by logging into your account and following these steps:

1. Click the [Your Username] > "Profile" link from the drop down top level navigation.
2. Click the "Edit Profile" button
3. Click the "My Privacy Settings" link from the side navigation
4. Check the box labeled "Always keep my total playtime private even if users can see my game details."

This will hide your stats!