Of the lenses you ahve which one produce images that you like. If you like how the 15-85 render then use it and be happy. If you prefer the 24-105L then use it. If you think you will need to use the 10-18 but wont' want to take the effort to switch it then don't take it.-
We can't decide what works for you or which lenses produce the images you prefer. These are personal things. For myself there was a time when I traveled with 4 lenses exclusive (25f2.8 or 28f2.8, 35-70f4, 50f1.4 or 85f1.4,135f2.8). Today I rarely take more than 2 lenses and usually i'm more likely to grab my phone then the camera (I greatly prefer the camera; just not the bulk compare to the phone ). -
I never liked the 18-55 or the 15-85 (which I like better than the 18-55) but while I hated the 18-55 I never hated the 18-85. That's me. My camera was an older model and maybe the sample you have is nicer or the body you use cause it to render differently.
I really liked the olympus 12-60 (this is not relevant to your decision) but the body I used it with sucked - even though it produced nice images on that body. Today I'm transitioning from m4/3 to fuji but still use both (but rarely use a camera).
I have never used the 17-55 but i hear it is very good but a lot shorter than 15-85 (I'm more concern about the long end than the short end - as 25mm is the sweet spot for myself on the short end (35mm). I never used the 24-105 (I hear mix things). I would never use the canon 5d; just too large for my taste (i grew up with om-1 and later used a contax aria).