Match Cover Letters with Job Postings

When I answer an ad I create a matrix with 2 columns: left side = the list of the job's requirements (or Job Description, etc.), the second column shows how I fit each requirement. I have used this in the body of my e-mail cover letter so the recipient doesn't even have to open any attachment.
Aside from making it easy for a human recipient to see that I am qualified for an advertised position, it has another advantage (and I am not making a joke): some resumes are scanned for keywords by computer, since I am using the advertisers requirements, my initial document will always pass the computer scan and get to the first human reading (like I said: no joke!).

When I apply for jobs where I may be overqualified I may just send the matrix cover letter as a resume; this has gotten me at least one interview.