A good resume is a well constructed, chronological summary of your work history, highlighting your accomplishments and responsibilities, beginning with your most recent job. Those of us who frequently read resumes prefer high quality light colored paper, with a type face that is easy to read. The old adage that a resume can only be one page in length is bunk. A two-page resume is fine. The reader does not want your life history, just a sneak peak.
Functional resumes are a tool of last resort.
Most human resource professionals, recruiters, and hiring officials do not like them. They force the reader to search through the resume for important information. If you must use a functional resume, do not oversell yourself. If your work history has been spotty, or you have moved frequently, it will come out in the interview. Direct it towards the specific business they are in.