I generally agree with anginaprinzmetal's observations. For an everyday watch it is hard to go past a Rolex DateJust or an Omega Aqua Terra, if your budget doesn't stretch quite so far (although the current 8500 calibre is not cheap).
While I agree that watches with black dials are less formal than white / silver, some other great, everyday options, are the IWC Mark XV or XVI or Rolex Explorer I (especially the older 36 mm models).
If you have large wrists, the Dornbluths are very nice, or Stowa Marine as a cheaper alternative. Another option, again with a black dial, would be the Omega Speedmaster Professional - while that is strictly speaking a sports watch it looks quite dressy with a leather strap.