I used to wear jeans all the time when I was younger, but as I've gotten older and a bit thicker I now find chinos to be more comfortable. The fact that they look classier is a bonus.
I still prefer t-shirts when it's warm, sweatshirts when it's cool, and wool sweaters when it's cold.
Shirts with collars are a problem because my arms are a little long for my body. If I buy them in medium they fit well but the sleeves are too short; if I buy them in large the sleeves are OK but they look baggy. Sweatshirts and sweaters don't pose a problem because it doesn't matter if they're baggy.
I probably look most stylish in winter with my wool sweaters and corduroy pants.