Seattle based civic software company and incubator FrontSeat.org has for the past few years been generating Walk Scores for neighborhoods in cities as diverse as Washington D.C., New York, Boston and Seattle. The company rates walkability based on the ability to accomplish errands and access local amenities without the use of a car plus other factors.

Here's their more complete description:
What makes a neighborhood walkable?
A center: Walkable neighborhoods have a center, whether it's a main street or a public space.
People: Enough people for businesses to flourish and for public transit to run frequently.
Mixed income, mixed use: Affordable housing located near businesses.
Parks and public space: Plenty of public places to gather and play.
Pedestrian design: Buildings are close to the street, parking lots are relegated to the back.
Schools and workplaces: Close enough that most residents can walk from their homes.
Complete streets: Streets designed for bicyclists, pedestrians, and transit.

Walk Score Description
90–100 Walker's Paradise — Daily errands do not require a car.
70–89 Very Walkable — Most errands can be accomplished on foot.
50–69 Somewhat Walkable — Some amenities within walking distance.
25–49 Car-Dependent — A few amenities within walking distance.
0–24 Car-Dependent — Almost all errands require a car.

Out of all Seattle neighborhoods they rank the Denny Triangle as the highest.

Here's how West Seattle neighborhoods ranked as of August 2, 2011 from www.walkscore.com :

West Seattle Junction is the #37 most walkable neighborhood in Seattle. This neighborhood is Very Walkable with an average Walk Score of 77. Junction has 5,868 people—or 1% of Seattle's population.
Junction is similar in walkability to Maple Leaf and North College Park. Junction's Walk Score is 3 points higher than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Junction

Fairmount Park is the #39 most walkable neighborhood in Seattle. This neighborhood is Very Walkable with an average Walk Score of 77. Fairmount Park has 5,171 people—or 0.9% of Seattle's population.
Fairmount Park is similar in walkability to North College Park and Ravenna. Fairmount Park's Walk Score is 3 points higher than Seattle's Walk Score of 74.

Admiral is the #44 most walkable neighborhood in Seattle. This neighborhood is Very Walkable with an average Walk Score of 75. Admiral has 11,276 people—or 2% of Seattle's population.
Admiral is similar in walkability to Bryant and Loyal Heights. Admiral's Walk Score is 1 points higher than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Admiral

Genesee is the #58 most walkable neighborhood in Seattle. This neighborhood is Very Walkable with an average Walk Score of 71. Genesee has 3,517 people—or 0.6% of Seattle's population.
Genesee is similar in walkability to Leschi and Roxhill. Genesee's Walk Score is 3 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Genesee

Roxhill is the #59 most walkable neighborhood in Seattle. This neighborhood is Very Walkable with an average Walk Score of 71. Roxhill has 4,231 people—or 0.7% of Seattle's population.
Roxhill is similar in walkability to Genesee and Sunset Hill. Roxhill's Walk Score is 3 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Roxhill

Seaview is the #67 most walkable neighborhood in Seattle. This neighborhood is Somewhat Walkable with an average Walk Score of 67. Seaview has 4,521 people—or 0.7% of Seattle's population.
Seaview is similar in walkability to Montlake and Dunlap. Seaview's Walk Score is 7 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Seaview

South Delridge is the #73 most walkable neighborhood in Seattle. This neighborhood is Somewhat Walkable with an average Walk Score of 64. South Delridge has 6,226 people—or 1% of Seattle's population.
South Delridge is similar in walkability to Magnolia and Interbay. South Delridge's Walk Score is 10 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/South_Delridge

Industrial District is the #77 most walkable neighborhood in Seattle. This neighborhood is Somewhat Walkable with an average Walk Score of 64. Industrial District has 516 people—or 0.1% of Seattle's population.
Industrial District is similar in walkability to Beacon Hill and Gatewood. Industrial District's Walk Score is 10 points lower than Seattle's Walk Score of 74.

Gatewood is the #78 most walkable neighborhood in Seattle. This neighborhood is Somewhat Walkable with an average Walk Score of 63. Gatewood has 6,550 people—or 1% of Seattle's population.
Gatewood is similar in walkability to Industrial District and Denny - Blaine. Gatewood's Walk Score is 11 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Gatewood

Alki is the #81 most walkable neighborhood in Seattle. This neighborhood is Somewhat Walkable with an average Walk Score of 61. Alki has 7,086 people—or 1% of Seattle's population.
Alki is similar in walkability to Meadowbrook and Broadmoor. Alki's Walk Score is 13 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Alki

North Delridge is the #83 most walkable neighborhood in Seattle. This neighborhood is Somewhat Walkable with an average Walk Score of 61. North Delridge has 4,229 people—or 0.7% of Seattle's population.
North Delridge is similar in walkability to Broadmoor and Haller Lake. North Delridge's Walk Score is 13 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/North_Delridge

High Point is the #85 most walkable neighborhood in Seattle. This neighborhood is Somewhat Walkable with an average Walk Score of 59. High Point has 6,582 people—or 1% of Seattle's population.
High Point is similar in walkability to Haller Lake and Hawthorne Hills. High Point's Walk Score is 15 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/High_Point

Highland Park is the #89 most walkable neighborhood in Seattle. This neighborhood is Somewhat Walkable with an average Walk Score of 54. Highland Park has 6,220 people—or 1% of Seattle's population.
Highland Park is similar in walkability to Laurelhurst and South Beacon Hill. Highland Park's Walk Score is 20 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Highland_Park

Fauntleroy is the #95 most walkable neighborhood in Seattle. This neighborhood is a Car-Dependent neighborhood with an average Walk Score of 48. Fauntleroy has 4,854 people—or 0.8% of Seattle's population.
Fauntleroy is similar in walkability to Matthews Beach and View Ridge. Fauntleroy's Walk Score is 26 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Fauntleroy

Arbor Heights is the #101 most walkable neighborhood in Seattle. This neighborhood is a Car-Dependent neighborhood with an average Walk Score of 41. Arbor Heights has 5,429 people—or 0.9% of Seattle's population.
Arbor Heights is similar in walkability to Sand Point and North Beach. Arbor Heights' Walk Score is 33 points lower than Seattle's Walk Score of 74.
http://www.walkscore.com/WA/Seattle/Arbor_Heights