I've worn black combats (name for cargo pants where I'm from) since I was a teenager if work policy allows it (or more correctly if no-one has yet told me it doesn't), they are comfortable, practical, hard wearing and I'm a programmer - what I wear should be like 207th on the list of things they should be worrying about.

As for brand, I visit the local workwear place and buy whatever they have in my size (usually dickies or similar) and move on - clothes made as actual workwear tend to be tougher and better made than 'fashion' knock-offs of working gear.