Dave,
To prove that Geoff is correct and what you have been told is RUBBISH !!!!
Here are 2 links to some images taken by my friend in the USA Kevin Dixon, with a 60mm (yes 60mm same size as the department store Tasco) Takahashi APO refractor.
http://www.kevindixon.westhost.com/Rosette_H-alpha.htm
http://www.kevindixon.westhost.com/R...Nebula-NBI.htm
http://www.kevindixon.westhost.com/H...NBI-FS-60C.htm
Here are a couple of images Kevin has taken with a 106mm refractor (4")
http://www.kevindixon.westhost.com/M16-narrow_band.htm
http://www.kevindixon.westhost.com/B...arrow_band.htm
As you can see from those images what you have been told is absolute RUBBISH in the 1st degree. Keep in mind that Kevin is using very high end equipment in every aspect of his imaging but notwithstanding it is only 60mm and 106mm of aperture only.
In terms of Geoff's comments about an 8" scope being the minimum size for pleasing visually astronomy, I would also agree with this and add a rider in that a skilled observer under dark skies can achieve a lot with a high quality 6" scope.
CS-John B