I think that it really depends on your level of service and then the needs or wants of the business. Granted, I can't say that I am much for cold calling especially in the areas of web design or hosting as I've been a web site designer and seo geek since 1995. And then I took all of my previous experience and skills and started a hosting company..
So generally, If someone calls about a service that I already offer, then cold calls are annoying.. It's like reading my inbox everyday to find all the latest hosting deals or web design deals.. And I think to myself... Obviously, this dude hasn't been to our site or seen the design... Now, I'm not a perfect designer but I consider myself to be pretty good to say the least.
But just like with every business, something comes along that either sounds like it can be useful or it just is.. These are the types of calls that really do not bother me..
So I think that overall, If you are in the web design business and you cold call to poeple who are not in the same business, then there is allot of room to pick up new clients here and there.. And the same goes for any other type of business..
Just my thoughts,
BTW: I also think that one of the easiest ways to generate new business for designers is to pick some popular software that support themes.. Offer custom template designs and work out some sort of deal with the company in exchange for giving you some business. I know that we've received requests before and since we offer hosting but no longer offer web design, there really is allot of potential business that just goes on by.. But the problem here is really finding designers that you can trust that won't just disappear.. That's probably one of the main reasons why cold calling work's for a designer who shows interest by calling a business. Because normally, a business will call or email a designer only to find that they never got an answer.