Well since Russell has shared an image as an example I will offer a couple of my own, of the same object Eta Carinae. The purpoe of putting these up here is just to demonstrate the difference that some types of mods can make.
Both of the images linked to below, are taken with Canon 450Ds, the difference lies in the mods. The first image was taken with my cold finger cooled colour 450D, this is a full spectrum modified camera thus the presence of much more Ha (Red) in the image colour. As stated before going full spectrum will give you access to up to five times as much Ha as a stock filtered camera will provide.
The second image was taken with my mono cold finger cooled 450D, this is also full spectrum (no filters in front of the sensor), but I run a EOS filter drawer on the mono camera and had an Ha filter in for this image. Thus the image is entirely Ha light, and only Ha.
Two things to things to point out: the mono mod of the sensor opens up a while new world of resolution as all the pixels are gathering light all the time (not like in the colour matrix covered sensor). There is a full 12.2 megapixel resolution capability. The level of detail is thus substantially better than the colour camera can produce. Secondly, the image content seems very different because the colour camera cannot 'see' what the mono camera with the Ha narrowband filter can reveal.
Eta Carinae, Full Spectrum Colour, cooled 450D on a Skywatcher MN190:
http://www.astrobin.com/full/185615/0/
Eta Carinae, Full Spectrum Mono, cooled 450D (with Ha filter) on Skywatcher MN190:
http://www.astrobin.com/full/243048/0/
Just a final word on cooling and dark noise. Canon 450Ds have been shown in testing (by rcheshire (Rowland), and myself) to best perform when the sensor has been cooled close to 0C. There is not alot more to be gained by going sub zero, and I have tested down to -15C. At 0C the Darks and Bias Frames become almost identical. A Dark (or Master Dark) library can then be easily created and negate the need to shoot them each time or track the temperature they were shot at. Obviously you still stack with settings to eliminate hot pixels, etc. I should add that most Canon DSLRs return similiar results when cooled to these temperatures. Cooling really works, but brings you into the world of condensation management - another topic for later.