Well, I'll join this discussion late as well. While I've never owned or held the 24-70 f/2.8, these are the lenses I do own:
10-22 f/3.5-4.5
17-55 f/2.8 IS
35mm f/2
50mm f/1.4
70-200mm f/2.8 L IS
I primarily shoot with a 50D. The 17-55mm lens is the most versatile tool in my bag. It stays on my camera 3X as much as any other lens I own. No, it isn't built like an "L" lens, but the image quality is certainly "L" quality, in my opinion. If you plan on staying with a crop body for a while, I'd advise going with the 17-55mm f/2.8 IS because it's the perfect general purpose lens. If you plan on upgrading to a full-frame body within the next two years, then I'd suggest buying the 24-70mm f/2.8 L.
If you want to see examples of my 17-55 examples, click here.
Thanks again for those who've chipped in and offered your advices.
As said above, I have taken the 24-70 for its build quality and less depreciation in the way onwards. I have to admit that the range is a bit long especially on my 1.6 crop body. 10-22 will be considered when it comes to be required for landscape shooting (not this year, cuz no more budget :P).
So far the 24-70 hasn't disappointed me. Its outdoor performance is great (image quality and color saturation/contrast). It performs as well as my 70-200 F4 IS USM. For indoor, the large aperture does help. It actually does better than my previously owned Sigma 30mm 1.4 HSM.
I was worried about its heavy weight. But it turns out not as bad as I imagined.
Today I am going out with kids to do some stress test with the lens. I will see how it goes!
24-70 L has a soft image. 24-105 L is preferred for me
I think you made the best choice with your lens purchase. The L series lenses hold their value very well where you can always turn around and sell them at any moment if needed. Like I mentioned earlier in this post my 17-55 IS lens sucked in the dust. The dust was not effecting the image quality but is was very upsetting to see my 1000 dollars plus lens do this. I had to have mine cleaned by Canon twice and then the third time I did it myself. Read how to do it on-line where it was simple to take apart and clean. Some people feel that the efs 17-55 lens won't collect dust but if you shoot outdoors in dusty conditions for hours on end it will inevitably happen.
SupraSonic: 24-70 L has a soft image. 24-105 L is preferred for me
The ISO 12233 test shots on this site show that the 24-70 is sharper than the 24-105 when both are at f/4.
Daniel Browning: SupraSonic: 24-70 L has a soft image. 24-105 L is preferred for me The ISO 12233 test shots on this site show that the 24-70 is sharper than the 24-105 when both are at f/4.
I concur. I have owned the 24-105 and presently own the 24-70. They a similar in sharpness in the center but the the corners on the 24-70 is substantially sharper. The 24-105 also suffers from heavy CA on the wide end, much more than the 24-70.
The 24-70 is probably my favorite lens at this point. It has produced some of my best and sharpest images.