I honestly don't think I have a single everyday "goto" lens, for the simple reason that I could wind up shooting so many different things.
I wind up using the TS-E 24 II a lot, more than any other lens, but it's probably not the only lens I'd grab if I was going to just go out with no idea what I might wind up shooting...though, generally, I have a pretty good idea of why I'm grabbing the camera, so I'll pick whatever lens is going to be best suited for what I'm headed for.
The 24-105 would be my choice for a "I truly have no clue what the hell I might encounter and I don't want to load myself down with a lot of stuff" lens. And, if I want to go even lighter, I'll take off the grip and slap on the Shorty McForty. But for most of what I wind up shooting, it's not even going to occur to me to grab the 24-105.
If I did a lot of events or other variations on the photojournalism theme, I'd have a hard time picking between the 24-105 and Tamron's stabilized 24-70 (which I've never seen in person). Or, I would have a hard time if I didn't already have the 24-105...I'd have to spend a long time shooting with the 24-105 and running into limitations from f/4 but not running into limitations from not having the extra reach, and I doubt I'd wind up thinking it's worth selling the one to get the other (in either direction).
Cheers,
b&