I tend to use Arial. As some of you may know from another thread ... I experience somewhat mild vision problems. I have tried many of the fonts discussed here ... but I find Arial the most easily readable when my vision acts up ... and many others with the same type of vision problems find Arial to be the most easily readable as well.
However ... if I need to use Italics (usually at the bottom of pages for Copyright info etc) I usually use Times New Roman
Take care
Peter