Optimal set of social share services for posts?

[redvel]

So I am adding/renewing social share buttons to posts on some of my sites. I wonder, what would bet the optimal set in your opinion? Traffic is mostly US and Europe.

I think FB, Twitter and G+ is a must. Than I am thinking of Pinterest, as it is on the wave now, also maybe StumbleUpon (had some good results with it in the past)?

What about Digg/Delicious/Reddit? As I am from Europe, I understand these are popular in US. Or at least was popular. Can some Americans comment on them?

I am also always including Email button, saw a tendency that people like to email interesting posts in higher traffic sites.

And finally I started to not waste my time on RSS buttons/links - I guess "normal" people (not geeks use it quite rarely. However, those normal people like to subscribe to new posts to their email, so I still create a Feedburner account for each of my sites and use its Subscription to email service.

What services you use/recommend?