Canon 15-85 (900$) vs Canon 85 1,8+Sigma 10-20 (1080$) for travel

Hello, evereone!

I am planning to buy a Canon 60d because I am going to travel to USA to shoot canyons, parks, cities - landscapes, architecture and street photo (portraits).
Would any of the two options give a better image quality or not?
Canon 15-85 f3,5-5,6 IS (900$) vs
Canon 85 f1,8+Sigma 10-20 f4-5,6 (total 1080$)
The rates are from Moscow internet shops.

Or you could reccommend anything else...