Back when I bought my first Canon dSLR - the 3 MP D30 back in 2000 - I bought a Canon 28-135 zoom.
For 8 years this lens has been flawless and amazing in its performance as I have upgraded through the 1.6x body line! I don't know if they're all this good, but man... Check out this image I did with it on my 40D. It shows this lens at its very best.
Click here to see 17.5 MP image done with 28-135 zoom (note: large file)
For this I shot raw (ISO 100, 1/200, f/7.1, 44mm) , converted in Photoshop (Camera Raw) to 17.5 MP resolution (the camera delivers 10.1 MP native), then used my own fractal sharpening on it to recover the slight fuzziness added by the upsampling.
I dialed in some slight CA adjustments during the raw conversion, and the software compensated perfectly for what little CA there was.
To date I've probably fired well over 50,000 images through this lens.
-Noel