I realize this is, at best, tangentially related to this topic, but a few weeks ago I thought about formatting and printing my resume on A4 for a job fair. My thought was that if I wanted it to stick out from the rest of them, why not have it literally stick out? I decided against it, but I do wonder what sort of impression that would give an employer; as a US employer, how would you react to a resume from someone, also in the US, but printed on A4?
I think my reaction would be the same as if I got a resume from someone printed on 8.5 x 11 paper -- I'd ask the candidate to send me an electronic copy via email. :)
Seriously, though, I've been the hiring manager for a number of positions at various jobs over the past ten years, and the main way of collecting resumes has always been electronic. This is for jobs in both the technical and editorial fields. On the rare occasion that someone mailed me a hard copy of his or her resume, I'd almost always question the person's technical literacy. Worse yet for the candidate, the resume was likely not to get looked at as closely as the others nor re-reviewed because it wasn't in the same email folder.
That's not to say there's no use for hard copies of resumes. During the interviews themselves, of course, it's helpful to be able to look at a piece of paper. But I would usually print out the resume ahead of time and take it with me when I met with a candidate. After that, if I didn't make any important notes on the resume itself, it'd go in the recycling bin.
I guess I should have said that I was at a job fair. I realize that I could have emailed my resume to the company before or after the fair, but I wanted to leave the recruiter with something tangible to both indicate my interest in their company and to display my relevant skills.
However, your comment has prompted me to send an additional, electronic version of my resume to all the companies I gave hard copies to. It can't hurt, and it might give it additional visibility.