In my field (Information Systems), most papers are served as PDFs. My advisor has switched almost entirely to his iPad for most work, especially when reading/annotating articles.

Most journals in my field require Word docs, and don't use LaTeX. It's been my observation that the field is filled with business people who use computers, and relatively fewer computer people who ended up in business. Sure, there are some of each, but the former seem to outnumber the latter.