Do you think Google +1 and Facebook Like are really important for the website...? Not every top 10 site got it....Or just in case Google change its policy and algorithm in the future...

It will be really good to listen your opinions

If you are writing relevant content (content that people are likely to find useful and share) then I definitely suggest it . Especially because its not that difficult to integrate.

I haven't been able to quantify the advantage of G+1 yet. Because I only jumped on that boat a bit later.
But I definitely do see a small increase in traffic due to FB Likes

They are both important, even more with the personalisation of search.

I would also look at linkedin shares, Twitter shares.

I get heaps of traffic from all social buttons even stumble upon/ Reddit too

__________________
Check out my sites: Sydney SEO and Social Media|SEO Australia |Professional SEO |Life Insurance Cover |
Backlinks
For Professional SEO and Social Media Consulting from a well known local consultant, Linkbuilding and more email: contact(at)professionalseo.com.au (Say you are from DNTrade, too be looked after!)