quote by amfoto1..."In addition to this, for around $200 it's usually pretty easy to find a lightly used Canon EF 28-135mm f3.5-5.6 IS USM.... and image quality rivaling that of the far more expensive 24-105L or even the 24-70L".
Wow, I promise you I hate to sound like a butt in disagreeing (but) as the OP and others will use recommendations; I have to disagree once more.
When I first went digital, I upgraded my kit lens (18-55mm) to the Canon 28-135mm and used it for several years. I always thought it was a good lens until I compared it to a first version Canon 18-135mm and the Canon 15-85mm. Those two lenses blew the 28-135mm away. The only exception was the annoying vignetting the first version Canon 18-135mm suffered from and poorer build quality.
I kept the 15-85mm, btw. The newer 18-135mm STM is significantly improved over the original version. The 28-135mm just doesn't compare IMHO and as Digital Picture confirms HERE.
quote by amfoto1...."24-105, 15-85mm, and even the 18-135s are all going to cost more... a whole lot more in some cases."
The OP can get a good used 18-135mm STM from $250.00 to like new at $300.00. I have one for sale HERE if interested.
I used to recommend the Canon 28-135mm but it's a poor recommendation now, given the superior quality of the newer 18-135mm STM with its' similar pricing.