What are the ultimate office slacks?

More detailed questions at the end!

I'm very new to working in non-uniformed office environments, about 2 years now. Somehow I have gone through more slacks than I care to admit. They easily get pulled threads, fading color, or pilling. I want to start a discussion on what the absolute best pair of slacks are.

Previously I've gone for at least 60% natural fibers and less than $50, but I think I need to up those to 70% natural and less than $80 to find something that will last at least 5 years. I've tried H&M, Uniqlo, and an array of other brands but they never last past the 1 year mark.

I want to hear from this community and see what you all have found in your search for the ultimate office attire.

What are your favorite slacks? Why do they work for you? Do they meet all your criteria for work pants (price, longevity, quality)? And how do you wash and maintain them?