does a cover letter have to sound like an informercial?

A reader writes:

I really appreciate your blog and your candor, and I have used your advice many times during my job search. In fact, the interview chapter from your e-book made a huge difference on my last interview and I really felt like I was on equal footing with my interviewer. It resulted in winning a contract for a project that went well and will hopefully lead to more work in the future.

My question is about cover letters. I have poured over your “example of a good cover letter” post, as well as the section on cover letters in the e-book, and it has again made such a difference in the way I see the issue from the reader’s side. However, the opening line of a cover letter is so challenging for me to write because I want to make an impact and say something more than the position title and the place I found it posted, but I don’t want to sound like an infomercial.

I’ve read some advice that suggests asking a question that the reader would answer "Yes" to, but examples of these sound like a used car salesman to me, and that is just not my personality. I’m applying for creative positions in a marketing and advertising, so I want to write an opener that would be interesting and make them actually want to continue on to my resume. What kind of cover letter openers appeal to you?

Ugh, I know exactly the sort of cover letter openers that you're talking about -- "Are you looking for a detail-oriented self-starter with a background in engineering?" and so forth -- and I hate them!

They sound overly salesy, and no hiring manager wants to feel she's being aggressively sold to.

Frankly, I think standard openers are perfectly fine. You don't need to have a gimmick, after all; just make sure the rest of the letter is compelling. "I'm writing to apply for your field organizer job" is straightforward and gets the job done.  

Or "I'm really excited to apply your field organizer job" would be a little more interesting (although be prepared to show that you really are excited and why).

Or even re-writing that salesy opener to something like this: "Reading over your ad, I suspect you're looking for someone detail-oriented and organized, and that's why I'm responding." For this one, make sure the ad didn't specifically list the qualities you cite here, or this won't work -- it's a good opener if it shows you read the ad and deduced some things on your own, but not if you're just regurgitating what they wrote. Although if you want to do the latter, you could change it to, "Your field organizer ad called for someone detail-oriented and organized, and I'm continually lauded for those qualities." (Again, be smart and genuine about this. If you write, "Your ad called for someone with an English degree and I'm continually lauded for mine," that won't pass a straight-face test. People are rarely lauded for their degrees by anyone other than their parents.)

But really, straightforward and basic is completely fine. The real action of the cover letter is going to be in what follows the opener.