Sirrith wrote in post #16243433
Unless your plans to upgrade are definite and within the next half-year or so, forget them and buy the most suitable lenses for the camera you have now. You can buy used and resell for little to no loss when and if you do indeed go FF. IMO it is not at all smart to limit yourself to FF-only lenses if you are not 100% certain you will be getting an FF body in the very near future.
+1. While the 17-40L works fine on a crop body, there are better options from Canon, Sigma and Tamron that will provide better range, image stabilization and/or faster maximum aperture. Get the lens that best meets your needs now, not for some undetermined future date where you may upgrade to full frame.
The Canon EFS 17-55 f/2.8 IS was my primary walk around lens when I only owned a crop body, and it was very versatile. I sold the lens when I added a 5D3 full frame body to my kit. I also had an EFS 10-22mm for UWA (still need to get around to selling that one). If I had to do it over again now, though, I would probably go with the EFS 15-85 IS instead, and supplement it with fast primes. This has been my approach since going full frame -- supplementing the 24-105L with fast primes, and adding a 17-40L for UWA.