The 5d MKII camera can produce some very high resolution images (21 megapixels) with little internal noise because of the camera build and design. Put it on a tripod... and use an "incredibly fast" light gathering lens like an f1.4...and boost up the light gathering ability by raising up the ISO some...and you could have some very very high quality, Hi res, base images to work from with this camera setup.
By using Photoshop adjustment layer curves with selective masking you can boost an image up about an additional 3 f stops in visual brightness...and with some digital noise reduction added in selectively...you might even be able to push that up some more.
My impression is that the incredibly bright lens, matched with the incredibly quiet Cannon camera, together with the non-destructive nature of curve layers...can give you some images that average joes would love to take...but cant.
Here is some mathematics: The cannon f1.4 lens is $1600 and the 5d body is $2300 and Photoshop CS5 is $600 and a fast computer is $1800...SO...if you have an additional $6000 to throw around at some good camera gear...then maybe you could make some better quality low light pictures like this guy did too...given some good planning and skill to go along with it too.
So, whats a guy with a $600 dollar camera and a very poor quality f5.6 kit lens going to be able to get for images...compared to this guy?? You could get some great killer shots at noon maybe!! LOL.