A pair of 22" 1920x1080 monitors is a good, inexpensive set up suitable for most applications. For anyone buying a new set up, a pair of matching displays is less than $400, maybe a bit over $500 for three if you shop for the best current deals. There's never been a cheaper time for multi display set ups.
The only issue with multi-monitor set ups is desk space clutter, but there are many types of monitor trees for dual, triple, quad and six monitor set ups that use a single mounting point or floor stands, eliminating the clutter.
Using an HDTV as a display is somewhat impractical for anything but gaming as the optimal viewing distance is further than desk viewing distances, but since HDTVs can pull double duty as monitors, why not have one of those extra inputs plugged into a PC if they're in the same room anyway?
