Selecting a Site
Every real estate agent will tell you that value is just location, location, location, although from a green building perspective, the market is currently undervaluing some of the aspects of location, and overvaluing others. While neighborhood type, views, and access to services and schools are often still important factors, walkability, safe bicycle routes, access to sunlight, noise, traffic, and sense of nature are often very important for green building.
Rather than a list of amenities, if you think in terms of the house as being part of both an ecosystem and a community, the question to ask before buying is "Do I want to live in that ecosystem and that community?" Some negative characteristics can be gotten around with house and landscape design, but difficult problems like darkness and excess traffic noise are always a challenge. Cost and availability often are significant barriers to getting an ideal location, so compromises will often have to be made.
It is best to know the limitations of the site before you even design anything. Here are some things that are often important:
Sun: there are three related issues here:
1) On-site energy: is there a building site that provides winter sun for passive solar (heating climates)? is there a building site where the western exposure is shaded in the summer (cooling climates)?
Is there a building site where the roof has full day sun for a solar electric system? If not, is there an acceptable alternative location? Likewise for solar hot water? Even if you don't want these things now, having a site that doesn't have sun means you can't ever have them (or at least not without cutting down the neighbors trees and/or house!).
2) Daylight: adequate daylight does not demand as much direct sun as on-site energy, but the light in the room will always be much less than the light outside the room, so if the outside is a little dark, the inside will be quiet dark. Its the primary reason that even tree lovers end up cutting back trees on a heavily wooded lot.
3) Food/place in the sun: Is there a place for you to grow your own food (even if its just planter boxes on a patio)? Is there a sunny place to hang out in? While not always desirable, there is almost always some season such a place is desirable.
Community: For many, neighborhoods are about status, but for many green building people, its mostly about community. In some wealthy neighborhoods, its seems the gardeners know each other more than the occupants. Community is about working together and being together in a way that makes people feel connected instead of isolated. People are inherently social animals, so when everyone keeps to themselves, they tend to feel isolated.1
In a city, a good neighborhood is walkable, either via sidewalks or pedestrian and bike paths, creating opportunities for chance meetings, while in a rural area it may come more from depending on each other.
Neighborhoods, mostly only urban ones also need green space: not just ball fields, but natural green space where you can relax. A good neighborhood has a grocery store, post office, bank and other commonly used services within walking distance: it is the one reason urban living can be more "green" than rural living.
Living in the country all too often means giving up the ability to walk because the roads are too narrow, there are no parks and trespassing is frowned upon.
From the environmental perspective, the best quality of a neighborhood is how often you do what you want to do and not leave it.
Quiet: No one really likes noise, although there are those who don't like quiet either. There is a difference between the sound of activity (ie voices and lower volume sound) and the sound of machinery, and few prefer the latter. The problem that arises here is that economics and/or commuting distance dictate where you live more than personal choice.
Super-insulation and good windows will mitigate noise somewhat, and walls, and dense planting can mitigate it more, but might also reduce the light coming in. Alas, loud traffic (particularly trucks), airport noise and industrial noise are hard to mitigate. Running water has been used in public parks, but on a residential scale, if you have to pump it, the energy use will be quite high, and not everyone finds the sound soothing.
View: the ability to look out over the neighborhood, or at water, or mountains is a great feature, but it often expensive. Homes located on hilltops are often windy and tend to feel exposed to the elements. Partial views can be a nice compromise.
Transportation: the ability to do some chores by walking or bicycle reduces the stress of driving. In that sense more compact neighborhoods often allow for more services to be available within a shorter drive. If there is functional public transit, easy access to it is a plus. In general the further out you are in suburbia, the more you'll have to drive, and these days the traffic is often as bad or worse than in cities where road systems have been improved over time.
Existing conditions: If your buying an existing house, keep in mind that homes in disrepair are usually overvalued because people grossly underestimate the cost to remodel. A house with charm, but no insulation and leaky windows may be great to look at, but isn't that nice to live in. Most houses are built with only considerations of the number of rooms, structural issues, cost issues, and building codes, so keep in mind that you'll either have to live with the layout, or face a potentially costly remodel.
It is almost always better to build on a disturbed site (ie already used) than to build on a site that has never been built on. There is little natural land left, so the more wild the site, the less desirable it is as a building site. If you must, minimize the impact.
Notes
1: admittedly few people living in those kinds of communities who would say they felt isolated. The people who do report it have generally moved elsewhere.