Cover letters are always a good idea when submitting your resume. It allows you to show some of your personality, gives you a chance to talk about your successes in more detail, and gives you a chance to personalize your response to a company. Even if it never gets read, is it worth the risk of being tossed aside because you don't have one?
A well thought out cover letter works when it comes to getting you an interview. In today's everyone is in a hurry with little time to sit down and read your whole resume, so a great cover letter is essential. You give the person doing the hiring a quick look at who you are and why you are the right person for the job. Never underestimate how important your cover letter is, a good makes you stand out against today's tough competition.
A cover letter does matter when it comes to getting a job. It can create a memorable impression, introduce a summary of your experience, and draw attention to your personality. Interviewers generally like and remember personable applicants. A skillfully-written cover letter can also outline what you have to offer, and what you expect. Most importantly, a cover letter can push your application to near the top of the pile.
The hiring process at most companies is a joke. Candidates are looked at based on a small number of criteria looking for the candidate that fits through all their hoops. While the resume itself is more important, the cover letter can still provide plenty of details that can help a candidate fit into the specific mould that a company is using to hire.