Recruiter here. I've written on this topic before (notably here
http://jobtipsforgeeks.com/2012/09/17/disrupt/), but a major part of the problem is the incentives built into the contingency recruiting model. It's a competitive rat race that is the reason behind both the incessant cold calling and the barrage of resumes sent to companies hoping that one will stick. It's an industry with no barrier to entry with huge potential payoff. I don't think most engineers realize how much good recruiters actually make.
I make relatively few cold calls now, as you shouldn't need to once you are established, but that takes time. The problem now is that there are simply too many recruiters in the marketplace (again due to low barrier to entry and high payoff), and contingency recruiting firms are more than willing to pay recent liberal arts majors from mediocre schools pennies to make calls all day (I'm qualified to say this with my Bachelors in Econ from Delaware).
Companies that farm out their work to 20 contingency firms fuel this fire. Find 1-2 good firms, pay them some money up front and make them earn the rest. My fees are much lower than contingency firms, because I'm willing to take less if my client is willing to absorb part of my risk. Contingency firm had 100% risk, retained firm has 0% risk (some variation) - find somewhere in the middle with a recruiter you trust.
If you are a company hiring manager or startup founder, tell recruiters your company works with recruiters at 10% fees - they should stop calling to solicit your business (but may start soliciting your employees, because in a world with finite talent resources, if you aren't a potential client you are a potential source).
If you are being called with opportunities, that is tough to solve, but making a reference on a LinkedIn profile that you are not interested in recruiter contacts should help. I make few cold calls, but always honor that request when I see it. Keep in mind - when I got into the business in 98, before LinkedIn and when you had to really hunt, many people were somewhat rude when called. A few years later when the market went south, these people became much more friendly. Recruiters don't control the job market by any means, and they are having less and less overall influence as an industry every year it seems as technology makes them a little less necessary. Be nice to them the first time, maybe take a second to tell them what they are doing wrong, set a guideline with them (you can ping me every n months)and if they pester you after that, do whatever feels right.