Basically anything (besides jeans and khakis) that isn't a matching two or three piece suit.
- Slacks and a button down shirt
- Slacks, shirt and tie
- Slacks, button down shirt and jacket
- Slacks, shirt, sweater
- Slacks, shirt, tie and sweater
Since it's corporate, you will always want to wear a shirt with a collar. Also, make sure that you always wear nice (comfortable) dress shoes and keep them polished and clean. Gnarly shoes will mess up any outfit.