The best information to put into your opening line of your cover letter is a name: the name of the letter's recipient or of a mutual friend. Name-dropping virtually guarantees that your letter will be read. To get attention, nothing beats the coattails of someone whom the letter's recipient likes or respects.

The second-best information to put into the opening line is a clear statement of what you want, followed by the benefits you offer -- specific skills or qualifications you have that directly relate to the qualities the hiring company seeks.

Don't waste space in your opening line by citing the source of a job opening notice ("I saw your ad in the KoKoMo Express last Sunday"). Handle that in the "RE:" line in the upper-right quadrant (below your contact info and opposite the recipient's name and address).