Planned density equals quality, sub-urban sprawl equals misery.

Designed density or ad hoc sprawl is an issue for most places these days. A discussion wrt Boston communities here came up with the following:

"...density is the secret to creating healthier urban environments - with safer streets, better schools, more vibrant cultural and commercial activity, more efficient public transportation, nicer parks, and a less degraded environment."

"It's very much about walkability. Goods and services have to be immediately available. You have to be able to walk to them."

"A five-minute walk in a neighborhood where you feel uncomfortable is too far."

via Kottke