It all comes down to your ride, I think. European cyclists usually have short commutes, as do I. I usually wear business casual but sometimes require something more upscale if I'm meeting with clients. Either way, I wear work clothes on the bike. I do, however, wear hiking or biking shoes on the bike (depending on whether I want to do any walking at lunch) and keep dress shoes at work.

Just a couple of changes to keep your nice clothes clean:
- Fenders are a must. A bike without fenders is like a car without a windshield.
- Don't overlubricate. A drop on each roller is plenty, and then wipe of the excess your next ride. Putting on too much oil is actually counter productive, since it will gum up faster.
- Keep your pants clipped, or, if you're in the market for a new bike, consider an IGH or single speed (depending on terrain) and then stick on a chain guard.

Of course, if you're riding for an hour each way, none of this really matters. Wear athletic clothes and then change when you arrive. Work clothes are great for the 10 minutes I spend on my bike each way, but impractical for longer, sweatier rides.