I guess its different, depends were you live etc.
-NES in the NES era we would call it Nintendo
-Once SNES/N64 came out we would call it Original Nintendo
-Once I became a NES collector I call it NES as in one word
- Many People in AUS, call the Super Nintendo, Super Nintendo or Super NES as in one word, not Super N.E.S
The results of this poll do surpise me though, saying it by the letters is more work and sounds kinda weird to me....oh well