The 24-105/4L IS is an excellent walkaround lens on FF. The time to buy one is as a kit with a new FF body, else pick up a "white box" version (where a retailer breaks the kit apart).
The 24-70/2.8L II delivers the best IQ for a zoom lens in it's range, better than some primes it overlaps, too.
The 24-70/4L IS is smaller and lighter than either of the two above, and does well for closeup (near marco) shooting, although working distance is limited.
If you're looking for a walkaround lens, I'd recommend the 24-105L. IS is great for static subjects, but does nothing for subject motion. If you'll shoot moving subjects (e.g. people) in low light, or portraits, the 24-70/2.8L II is a better choice.