If you are not using the lens 15-85mm any more, trade it with 24-105L with little top up.
If I could, I would sell the 40D and lens but, my wife wants my daughter to use the camera, so selling it isn't an option now.
I agree that a white box 24-105L would be a great option, a really nice FF std. zoom for a reasonable price.
Assuming the 70-200 is your only EF lens currently, and you don't have the money saved yet for a 24-105, maybe a 40mm pancake would temporarily cover the sub-70mm range until you have money saved up for a 24-XX zoom?
I do currently have an old 35-80 f/4-5.6 II. Not quite wide enough, or fast enough. I can only save my money slowly so I don't want to buy an interim lens and start my savings at zero again. I have the 50mm 1.8 II as well for the low light situations, but indoors I need to go wider sometimes and can't always back up. I am eyeing the 24-70 f/2.8, the older version (used), but might settle on a new 24-105. It depends on how fast I can save the money. Given those two options, which would any of you go. Speed of the 2.8, or reach of the 105?"