For those using the Sony D50 and similar for stereo ambient sfx, do you favour setting the mics at 90deg. or 120?

Cheers.

It depends on what the sound fx is, for ambiences I use 120 but for more spot fx I use 90.

Tend to agree with Gary. The wider stereo spread can be reduced if required but not the other way around. For mono stuff I point the mic's forward and then take one side of the recording.