[The 24-105 works very well on a crop as do all EF lens. The sweet spot of the lens is in the middle, so having the large EF sized middle means good IQ right to the edge.
I know the standard advice from enthusiasts and photo stores is "get best L glass no matter what (your budget is)". But again - except for the build quality, a 17-55/2.8 will do better on a crop body than a 24-105/4 due to the larger aperture: more creativity, faster af. Any you'll certainly get better pictures and more fun if you put your money into a ef-s lens like the 15-85 that actually is made for your body and put the remaining bucks you didn't spend for L glass into a flash like the 480ex2.
I would seriously consider the 10-22 plus 24-105 option. 105 on a crop will give you decent telephoto anyway (168mm FF). Probably get the 24-105 first and save up for the 10-22. Personally I would hold off on everything else until you get your essential lens.
Good advice, if you are set on a L ef lens on a crop body and are into changing lenses frequently - personally, I hate it. And if you've got a wider lens, you can still crop from your 18mp sensor to get objects further away. If you've got a narrow one, then you've got to step back - if you can. Thus my advice: For a crop body, at first only get the 15-85, this range is covered by so many Canon and 3rd party lenses for a reason.
All good points and I agree. A few more things to mull over to help your decision:
- All 3 lens (15-85, 17-55, 24-105) have IS and a similar price--15-85 a little less.
- If shallow DOF is important, then the 17-55 wins
- The 15-85 has a variable aperture. Barely moving off 15mm and you are already at F4 so the F3.5 is only at the very widest
- The 15-85 is an excellent focal length for walk-around
- Haven't owned the 17-55 but I believe it has a little better IQ than the 15-85.
- I would only recommend the 24-105 in conjunction with the 10-22 on crop bodies even though I have a 24-105 for my 7D and no 10-22. Instead, I have the 16-35, constant aperture and weather sealing are important to me.