I'm unfamiliar with the 24-105, but I'm instinctively predisposed to convince anyone to avoid getting the "kit" lens. The 24-70 or the 16-35 is the go-to lens of many photographers. From my [LImited] experience, the 24-105 just isn't a lens people buy to act as the cornerstone of their equipment.
I received my 5Dii a couple days ago, and haven't been so enchanted by a camera since my original upgrade from a P&S to a Rebel. I was very close to dumping my fisheye, because I was extremely unhappy with results I got with my 40D, 50D, and 1Diii...but, I couldn't bring myself to take that lens off the camera this weekend. That leads me to believe this camera makes a lot of average lenses seem great...and can make a great lens legendary.
Ultimately, the kit lens is classified as "L" caliber and is probably a great jack of all trades lens....However, I think you'll be happier purchasing a specific lens that suits your particular purposes from the start. If you're gonna drop that kind of cheese on a body, I'd hope you have a specific use in mind, and would want to buy the lens that allows you to best achieve that use.