What I use
I show PDF slides (I rarely need to embed content that requires anything
including Adobe Reader will display fullscreen (press Ctrl-l in
acroread). When possible I use
impressive (formerly keyjnote).
It provides fast transitions and pressing tab gives a contact-sheet style
preview for rapidly finding slides in response to questions. I turn off the
distracting animated transitions between slides. I have three additional files in my
present script sets options I like, the .py file
(which present uses) adds a feature allowing me to jump to slides by number, and
the .png file provides a big visible mouse pointer for presentations projected
to multiple screens.
I’ve also had PDF Presenter Console and it’s fork pdfpc recommended to me. The newer fork can display thumbnails of all slides and jump to slides by number. The advantage over impressive is that the program displays a timer and the next slide on the laptop screen, while displaying the slides to the projector. I haven’t swapped to this program from Impressive (yet) because the multiple monitor setup doesn't work robustly enough for me.
If you want to do fullscreen postscript instead of pdf, I’ve found pspresent to be a neat and tiny utility, which compiled and worked first time for me.