The A750 already has more features than the A650 (1GB of flash memory, USB port that can play video vs. only picture and music on A650, etc.)
The A850/860 is actually a slim-bezel version of the A750 with DLNA added. Both A850/860 and A750 have CCFL backlight.
The A760 features Samsung's 2nd-generation LED backlight with local dimming. The LED backlight system now has more clusters than the 1st generation. Its performance should be very close to that of the A950.
The A950 will be Sumsung's ultimate LCD experience. It's going to be the XBR8's rival. From their first impressions, some AVS forum members claimed that black level and contrast rivaled even the Kuro[Pioneer].