Mark makes a great point... Your choice of camera strongly depends on your telescope and your imaging preferences...
That said, your question simply states "CCD or DSLR" Given everything else the same.. Ie, same megapixel resolution, same pixel size, same physical dimensions of the chip (best example of this would be a QHY8 vs Nikon D50 as they both use the exact same Sony CCD sensor) then the cooled astro camera will be a better choice than the DSLR for astro imaging..
Once you start looking at the differences between specific CCD's then the waters get really really muddy...
For galaxy hunting, you may not require a super sized sensor, however you would go for a camera that would suite your telescopes focal length with regard to both pixel size and field of view... Alternatively, if you were looking to shoot wider extended nebulae, then you may want a much larger sensor, at the expense of going to larger pixels..
Essentially, you want a resolution of under 1 arcsec per pixel if you want incredibly sharp images with smooth stars etc.. I image at about 3.5 arcsec per pixel (which is fairly horribly under-sampled) however for what I image, it suffices. When I can afford something with a sensor the same size as the SS Pro, but 16mp giving me 1 arcsec per pixel then I'll do it..
There are SOOOOO many things to consider when looking at buying a camera for astronomical imaging. not only should you consider DSLR/CCD, but consider pixel size, sensor size, colour or monochrome, quantum efficiency, ABG or NABG, what you want to image the most, what optics you plan to use both now and in the future... It can be daunting, and the best answer is this...
Get yourself the following..
Canon 40/50D DSLR.
Starlight Xpress H9
Starlight Xpress M25C
SBIG ST10XME
FLI ML11002M
FLI PL16803
From there, you've pretty much covered all your bases.. Maybe throw in a SBIG STL1001 for super long focal length imaging too
So yea, spend about 100k on cameras and you SHOULD be covered for 90% of possible telescope options