I would actually go single speed first. You will spend less and have almost no maintenance issues. Don't worry too much about what sort of components you throw on because the main issue is getting the distances to work. Surly and Shimano make almost everything you'll need, unless you want some fancy Sugino track parts.
If you go the single speed route, gear it a little on the low side. A low geared SS is one of the most relaxing things in the world to ride.
You can convert almost any frame to SS, so just find something you like (MTB or road) and have at it. Since theft will be an issue this could be a good thing and make for a good first city bike. You may get another later, but I would start with the thing you can ride anywhere.