Do recruiters and employers generally prefer receiving a resume in a Word Doc or PDF if given a choice?

Unless PDF is mentioned in the job postings I highly reccomend that job seekers use .doc format (work). To avoid the problem of older versions of word, you may save your work as .doc (word 2003-2007) not the latest format .docx. Most employers have not updated to the latest version of Microsoft Office.

Some Applicant Tracking Systems (ATS) applications which allow you to apply for a position online can't read PDF, so you may provide a PDF if the recruiter/employer says they will accept that format. Otherwise, I would stick to MS Word. If the ATS can't read the resume, you run the risk of that resume being removed from consideration and possibly without notice.

Scarlett Career Services Helpful Tips: 

* If this is for an online application, use a Word document for where the resume is to be uploaded. And then upload a .pdf version where the application asks for additional documents.

* If it is being sent to an individual,  I recommend enclosing a Word version only unless noted otherwise in the job posting.

Is a summary of your background something that really should go on your resume?

Absolutely. Professional Summary sells you! 

If you can make it a bulleted list, even better. Employers can scan it more quickly. Additionally, a rambling summary does you no good. Short, sweet and job specific focused if at all possible.  There is always a debate about what goes on the top of a resume, but I strongly advocate for a simple branding statement that describes the key attributes and nature of the person that would set him/her apart from the competition. Not a list of skills, past positions, or responsibilities.

 It is the place for a "meta" statement, to give everything else a context. For a mid-career individual, it should be 2-3 lines in length - maybe a bit more but not by much. A focused summary bringing value to the reader. Informing an employer, that you're a "jack-of-all-trades," no.  A well-written resume will "sell" rather than "tell." You attract attention of potential employers with your resume by emphasizing the benefits and value you have to offer and can bring to their organization. (TIP: It goes beyond a general summary and laundry list of core duties and responsibilities!)