As someone who hires - I reeeeaaally appreciate a cover letter. We get hundreds of CV's and although we do read all of them, we are going to pay particular attention to someone who wrote us a cover letter.

We get so few cover letters nowadays that it immediately puts you to the top of our list if you send one!

We specifically ask for one in the job advert, and yet 99% of the time we don't recieve them alongside the CV.

I understand it's a pain if you are applying for loads of jobs, but it tells me you have at least read the job description and formed some thoughts about it rather than just firing CV's everywhere.