Some of the hiking pants are pretty hard to tell from just casual pants. Kuhl is a good one for that category with lighter fabrics. You might also look at things sold more as travel pants, like Eddie Bauer. I'm sure someone will recommend lightweight "tacticool" pants, but those are not really any cooler than jeans to me and likely not appropriate for an office job. Some of Dickie's stuff is lighter. Not the most stylish and the durability is variable. Uniqlo might also work as being slightly more durable than your average mall store, but don't expect to do hard labour in them. More offbeat suggestion - Utilikilt. There are also some other good sport kilt makers out there, but very much if it seems too cheap to be true, it probably is.