Phone versus Email for cold calling is a bit of a religious war. Your typical battled-hardened sales veteran tends to the "Pick Up The Phone You Wimp!" view; where the Twitter-savvy, IM-friendly yoof will be more inclined to send an email. In general. Personally, I fit firmly into neither demographic, but I am a fan of the veterans' view. In my experience, much of the arguments for email and against phoning are simply thinly disguised (or maybe subconscious) call reluctance. A recent example demonstrates why at least in my case, sales prospectors are pretty much wasting their time with email.
You run a small business. The economy that is rocking behemoths like GM is threatening to swallow your little boat whole, or smash it against rocks. Your car just broke down. You've just found out that your cholesterol is dangerously high. And your oldest kid is getting into trouble at school. What do you do?
There are two ways - one bad and common, the other rare but good. The first, I'll call the "If Only" way; the second, the "Despite" way.
The "If Only" way responds to problems by imagining and longing for a world where the problem does not exist. "If Only" I hadn't started my business in 2008. "If Only" I'd taken that safe job. If only my client hadn't gone bankrupt and became unable to pay my invoice. And it involves thinking enviously about the lucky people who are not experiencing your troubles. Basically, it is to live with the worldview that life is supposed to be easier than it is.