I've traveled pretty extensively with my 60D setup, and everything fits pretty easily into my backpack (minus the bigmos, I just bought that this week for an upcoming safari trip). With the T5i you'd have the same crop sensor field of view. These are the options that I would recommend-
Wide Angle (both excellent, I have the sigma):
Walk Around (personal preference, pick one):
- Canon 15-85 - probably best all-in-one solution
- one of the 17-55/50 variants (Canon, Tamron Sigma in similar focal lengths)
- Canon 24-105L - not wide enough for most people on a crop, but I love mine. I have the UWA when I want wider and its still a very versatile lens on the crop with great quality.
- Canon 55-250 IS
- Canon 70-200/4L - I only use my telephoto occasionally, it does well outdoors when you've got good light.
Low Light Prime:
- Canon 35/2 IS
- Sigma 30/1.4 - I have the original, nothing but good things to say about it. Great for food photography and walking around hand-held at night.
I only recently picked up the 24-105L because I was swapping lenses too often from wide to normal, and I plan to eventually go Full frame. Prior to that I used the 30/1.4 as my main walk-around lens since its a great all-around focal length on crop. I use wide to normal for most of my travel shots, and most of the ones I end up printing are from the 10-20. I use my 70-200 by far the least out of my kit, but its light enough to carry since I have the f/4 version.