A Poor Person's "LCD" Projector
Most classrooms in my school have an internet-connected PC. Most rooms have a large TV mounted on the wall. There are very few LCD projectors at our school. I use a PC-monitor-to-TV converter to allow the TV to mirror what is on the PC's monitor.
Based on cost, I chose an Avermedia AverKey iMicro converter. There are several other manufacturers. A TV screen has lower resolution than the PC monitor, so the display image is rather muddy. It is adequate for presentation software slides and displaying images. Occasionally, a student in the far corner of the room may have to move closer.
Given the variety of PCs and software I use at school and home, I find the html format the most portable. The appearance of an html page can be controlled through the use of style sheets (css). This allows one html file to have a different tailored format for viewing on a monitor, printing, or displaying on the classroom TV. For example, this page will print differently than it is displayed; the menu is not printed.
I can also add content that prints but is not displayed.
I use a feature of the Opera web browser to enhance the use of a TV in lieu of a LCD projector. The Opera browser in full screen mode (F11) recognizes the "projector" style sheet media type. My style sheet tells the full-screen mode web browser to increase the displayed font size. This (and other changes) presents the html content on the TV in a way that minimizes the shortcomings of the PC-monitor-to-TV converter.
Thus, I need only create one html file, but that file can be viewed by an individual at their PC, printed without inappropriate content for paper and projected for my classroom audience. Sweet.