Noise schmoise, keyboard cowboys, etc.
I'll let these images, taken with my now-sold 40D do the talking.
The Constellation of Scorpius
The Tarantula Nebula (NGC 2070) in Dorado
The Sculptor (NGC 253) in Sculptor
The Pleiades (M45) in Taurus - Mark II
The Butterfly Cluster (M6) and Ptolemy's Cluster (M7) in Scorpius
The Belt and Sword of Orion in Orion
The Orion Nebula (M42), de Mairan's Nebula (M43) and The Running Man Nebula
NGC 4945 in Centaurus
NGC 6188 in Ara - Mark II
The Southern Pinwheel Galaxy (M83) in Hydra
The Lambda Centauri Nebula (IC 2944) in Centaurus
The images of M45 and M42, out of the whole lot, are ones that are most affected by noise. The Orion one in particular was shot on a summer's night that was 26 degrees at midnight.
I will reiterate that a spectrum-enhanced 40D is a magnificent system for astrophotography (for someone not able to afford the latest tech, or isn't after a cooled CCD).
H