If I needed a "professional looking" watch by tomorrow, I'd just go somewhere with a generous return policy like Walmart, Target, etc. Buy something for under $100. Return it if you don't like it next week. Timex, Armitron, whatever. Unless you're showing off the name (which is pretty much the point of spending more than a couple hundred for a watch - pure vanity) or putting it under a magnifying glass, it will look as professional as most any other watch.
Just know what you're looking for. No digital watches. No yellow or orange or bright blue faces. White, cream, dark blue or black. No two-toned cases or bracelets, no plastic or rubber straps, no fake jewels. Either all silver or all gold metal. Metal bracelet or leather strap.
If you want something "dressy", skip the chronographs and go with as simple and un-busy of a watch as you can find. Something like this, under $60: