Why choose just one format?
I haven't changed jobs in over 5 years, but when I was last hunting I created my resume in several different formats - Word, PDF, RTF, TXT, ODF, HTML, dead tree - and could readily submit it in whichever format the interviewer/recruiter wanted. I actually didn't own MS Office (not broke, just stubborn); To create Word files I was working in OpenOffice and exporting to .doc format, then using the free MS Word Viewer to check for formatting errors.
I'd be surprised if most places didn't tell you up front what their preferred format was. If they don't, perhaps you should show some initiative and ask? If they want my resume translated into Klingon and saved as a WordPerfect document, that's how I'd give it to them.
