there's TONS of comparisons between the f8500 and vt60. the st60 and vt60 are pretty similar except for a couple features. there's also a ton of comparisons between the st and vt, so you could find everything you need by searching through here.
to get you started:
f8500 is brighter, has better contrast, and 'appears' more clear due to larger pixel structure(less space between pixels), and has a more aggressive screen filter
st60 may be a touch blacker, provides better motion resolution, and is a heck of a lot cheaper.
Displays: Samsung PN64F8500/JVC X35
AVR: Pioneer VSX-1018AH, 5.1 audio
Sources: HTPC(Mediabrowser), PS3, XBOX360, Wii, Sony DVP-CX995V
Control: Harmony One