which dpi to use on large screens

[Dark Atheist]

by large screen i mean the tv i have it connected to by dvi to hdmi - 37" LG lcd, from a distance (about 8ft) the writing looks rather small (even in media center) but if i use 120 things look a bit chunky (fonts), have tried ajusting them using 110, but even that looks cack.

Normal use is about 4ft away from the screen - changing between 96 and 120 is a pita and requires a reboot each time