What’s the best social media tool to start with in the Middle East? (Blog? Facebook? Twitter?)

With the 44 million Facebook users in the Middle East (representing 4% of Facebook's total population of 1 billion), then definitely Facebook.
Facebook is where the average Middle Eastern internaut is, which makes it the best place to start a social media campaign.

Depends on the country; In Jordan for example, large numbers are on facebook KSA & Egypt more into Youtube (KSA has 5.2Mil on twitter) Kuwait more into twitter & instagram than facebook

There is no "best" social media platform for a company to start up with in the Middle East.
I believe it all depends on the target audience and the services/products you are selling.
I do believe Facebook is a standard though.

I believe all major leading social media platforms including Facebook (Including Business Pages, Groups & Communities Development & Management), Twitter, LinkedIn (Company Page, Groups Engagement), Blog & Google+ are all the main essential factors and a key success to any organization not only in Middle East but from all over the world.
Most of the clients whether they from Middle East or from other region concern with the 1 most repititive question i.e.
"WHY SOCIAL MEDIA MARKETING FOR YOUR BUSINESS?" Well the answer is so simple, Social Media assists in many internet marketing phases including your online business expansion, for Product Branding, Develop Marketing, Online Advertising, and Social Engagement of your website, assists in increasing customers & in building customer trust.
Social Media Optimization process assists social visits to your website.
Keep posting and updating content to pursue users to return regularly.
With the arrival of social media, consumers have become major contributors, contributing to brand messaging.
Social Media Marketing plays an important role in enhancing your website visibility and keyword rankings in the major search engines that results in leads generation and a prior-based online exposure.
Have a nice day to all.
Syed Waqas Saghir Internet Marketing Expert, SEO Consultant, Social Media Evangelist.