The only dress code requirement I have is really 'no jeans, no sneakers'. And to be somewhat conservative. Colleagues range from khakis and button down to SC + trou, sans tie.
Since I can, I wear a very conservative yet semi-formal wardrobe of suits and shirts. Basically all navy and grey, white SC FC shirts and a solid navy tie and white TV fold linen PS (albeit, with full-strap penny loafers, not lace-ups). Actually that's pretty much it. Ties are grenadines or cashmere, links are simple MOP double-sided. Suits are not all solid, but any pattern is very, very subtle and fades to solid from a few feet.
Off the clock, unless it's an occasion or context where open-collar makes more sense (or is requested by any given woman), I'm always in sportcoat and tie (still solid navy, but wool or cashmere), but very casual ones - textured wool, blends and cotton and linen, and shirting is all soft BD collars, whether solid or uni stripe OCBD, gingham, windowpane, plaid, etc. And my PS's are puffed (cotton), not TV folded, and generally patterned.
Bottom line: I strike a balance by getting my dandy on outside of work, just as casual as you can go with SC + tie, and get my suit on at work by making it as conservative as possible.
Works for me, FWIW.