This is a great question. I have been recruiting I.T. professionals and Executives for many years. I tell them all the same thing. The key is in getting the resume in front of the person who will make a hiring decision. So unless you have a personal relationship with that person, someone has to first "find" or "notice" your resume. That could be the hiring manager, an HR person, or a recruiter.

For most people, submitting your resume to a want ad tends to be kind of a black hole. So your resume has to have enough info to get a decently high search ranking wherever it is posted. Don’t have a posted resume? That’s okay, LinkedIn ranks very high in search rankings if you have the proper key words worked into your profile.

For the resume proper, 1 page, 2 pages? The answer is put down as much as it takes to get your job history down. Give detailed descriptions for the last 7 to 10 years, then list the companies and job titles beyond that.

Just putting down the names of the companies and a title for all jobs won’t do. When scanning a resume (and that’s usually all that happens) the reviewer generally looks for:

1)keywords that apply to the job for which they are hiring
2)job titles
3)specific duties as they apply to the job
4)job history
5)overall tenure

Functional resumes are nice, but won’t tell the whole story. Many companies have a specific profile by which they like to hire. You can’t get that from a functional resume. Put the functional part up front as an attention grabber in your summary and accomplishments. Then list the job history as stated above.

A designed resume is fine. You at least want a resume that looks professional. But many times, the resume that ends up in front of the hiring manager has been stripped of formatting. If you want to show off your design abilities then list a link to your web site or blog. 

Don’t tease with only minimal info. But don’t list a whole page for any one job either.  One or two solid paragraphs and some bullet points is good. Talk of your specific duties. Okay, you were an I.T. Manager. But that means different things in different companies.  Were you in charge of the network or application development?  Were you do hands on or just managing?  What tools were used?  How effective were you?

Listing specific results is powerful.  Did you save or make the company money?  Did you get your projects done on time or under budget?  Use actual numbers to help sell your accomplishments.

You want your resume to serve two purposes. Get you noticed or found, and tell your story. Key words and specifics. Make sure your story is told well and you’ll make the cut if you are right for the job.