the f8500 is like an LED/plasma hybrid. it's a great way for an LED user to get into plasma.
totally uniform backlight and decent motion that you get with plasma, but also has nearly the same brightness as LED's. i have my cell light at 50%(i'm used to plasmas) because i find it too bright to watch comfortably.
i would suggest the f8500 for sure. OLED will be the only significant improvement between now and when plasmas are no longer sold. you MAY save money if you wait for the H7000, but i've heard nothing that would suggest it will be in any way better than the f8500.
Displays: Samsung PN64F8500/JVC X35
AVR: Pioneer VSX-1130K, 7.1/5.1.2 audio
Sources: HTPC, PS3, XBOX360, Wii
Control: Harmony One