I've got four rules for recruiters, usually (but not always) I delete a recruiter email immediately if they violate any one.
- Address me by name (many recruiters do not bother such a simple courtesy).
- Talk to me about the position (many recruiters say in their first contact "do you or someone you know..")
- The position offered is actually inline with my current skill-set.
- Recruiter is respectful in each contact.
Simple, aren't they? You'd be surprised at how few can meet this criteria.