Up to this point, the items on this list have been mainly about avoiding things on your résumé that are unnecessary and might disqualify you from even being considered for a job. Now we're going to change gears a bit and get into résumé style. None of these résumé elements are absolutely fatal flaws, but if you want the best shot at the job, you should leave them off.
Traditionally, people have tried to account for lengthy employment gaps on their résumé. The problem is that there's rarely a good explanation, and if there is, it's rarely relevant to the job at hand. The best way to avoid the problem is to use a different type of résumé – functional, rather than chronological. Instead of listing all your jobs (and gaps) in order, rank your past jobs by how relevant they are to the one you're applying for and how well they show off your skills and experience. Then put them on your résumé in that order, with the dates of employment a minor note instead of the primary focus.
Employers may still notice gaps and ask you about them at the interview, so have good answers ready. Still, it's much more natural to explain in person that you took two years off of working when your first child was born than to use a bullet point on your résumé that says, "2003-2005 – raised a kid."