How do you prefer potential suppliers to make contact with you?

As a Business Development Manager with a Print Management company, I am constantly being told by my peers and industry experts that cold caling is dead. Funnily enough, my greatest successes with winning print management contracts have been from cold calling a procurement or marketing manager, after some research on the most appropriate person to contact. I'll generally research an organisation and try to find some similarity to my current clients or a value add I think we can bring to the prospect. Social media such as LinkedIn and Procurious are great for building a network, but I find some professionals don't feel it an apropriate medium to contact them on. They see their social media identities as their own, separate from who they work for. So for you Procurement professionals - how do you prefer a potential vendor to make an initial contact with you and what should they do during this contact for you to consider them?