3 pages is also too long.
I typically will not read cover letters (and letters of recommendation) that are longer than 2 pages. I prefer cover letters (and letters of recommendation) to be 1 page. Those of us who have been on search committees know how annoying it can be if people submit long cover letters and applications (unless we explicitly state that applications should be longer--similar to a resume').
It takes enough time to read resume' and supplemental information. Imagine having a large applicant pool and all of them thought they were important enough for pages upon pages of STUFF. LOL. When I'm on a search committee I stop reading after a while and I
may skim the rest. If your awesomeness wasn't revealed in page 1 or page 2 (at the latest), I will miss your awesomeness.
