10' from a 64" would probably be on the FAR end of the scale actually.
I sit about 12" from mine, but the room is set up for a 120" projection screen. if I were watching scope movies on my f8500, i'd probably want to be about 5-6feet away. far enough I can't see any dithering, close enough I can feel the immersion.
Displays: Samsung PN64F8500/JVC X35
AVR: Pioneer VSX-1018AH, 5.1 audio
Sources: HTPC(Mediabrowser), PS3, XBOX360, Wii, Sony DVP-CX995V
Control: Harmony One