st60 best value by far
f8500 best tv by slight margin
f5300's really only become popular because it's the only good plasma left for a reasonable price... last year it was 'meh' in the market for of cheap Panasonics(like the s60 and st60).
unless things have drastically changed since last year(when I was shopping), I would say the st60 is 95% the tv the f8500 is, it's 10% worse in a bright room, but 5% better in a dark room. the f5300 is decidedly third place in both situations. respectable, but imo it's price fairly. the st60 is priced much lower than it should be.
Displays: Samsung PN64F8500/JVC X35
AVR: Pioneer VSX-1018AH, 5.1 audio
Sources: HTPC(Mediabrowser), PS3, XBOX360, Wii, Sony DVP-CX995V
Control: Harmony One