From the replies, the strongest value pick is the Tamron 17-50mm f/2.8. Multiple users recommend it as a walk-around lens on Canon APS-C bodies, praising its sharpness and constant f/2.8 aperture. That wider aperture is useful for people shots, lower light, and subject separation, while 17-50mm still covers landscapes, city scenes, and everyday use well.

The Canon 15-85mm is also recommended as a very strong all-around option because it gives you more range on both ends: wider at 15mm for landscapes/architecture and longer at 85mm for tighter shots. It’s described as fast, quiet to focus, and excellent in image quality. The tradeoff versus the Tamron is that the Tamron’s constant f/2.8 is better if you prioritize speed and low-light performance.

So the practical choice is:

• Tamron 17-50mm f/2.8 if you want the best value and a fast standard zoom.
• Canon 15-85mm if you want maximum versatility in one lens and can find it within budget.

If your shooting is mostly landscapes/cities/people, the Tamron 17-50mm f/2.8 is the safest recommendation from the community.