On Thursday, real estate site Zillow will officially announce that San Francisco ranks tops when it comes to trick or treating. San Francisco climbed to 2nd on the 2010 list, trailing behind Seattle, but now Baghdad by the Bay reigns supreme when it comes to handing out fun-size, high fructose, corn syrupy treats. The "Zillow Trick-or-Treat Housing Index" uses four data variables: Zillow Home Value Index, population density, Walk Score and local crime data from Relocation Essentials.

For your amusement, here are the top 20 U.S. cities in which to trick and/or treat:

1 San Francisco
2 Boston
3 Honolulu
4 Seattle
5 Chicago
6 San Jose, Calif.
7 Washington
8. Los Angeles
9 Philadelphia
10 Portland, Ore.
11 Minneapolis
12 Pittsburgh
13 San Diego
14 Cleveland
15 Miami
16 Denver
17 Milwaukee
18 Virginia Beach, Va.
19 Baltimore
20 Albuquerque, NM

Zillow's theory? Here you go:

We theorized that homes in more expensive neighborhoods would give out bigger, better candy. However, wealthy neighborhoods are not always the best for harvesting the most Halloween candy. For parents and kids alike, the walkability and density of a neighborhood is key to covering the most ground, in the fastest time, to collect the most candy. Safety, of course, is also a primary concern for parents on Halloween, thus adding crime data to the Index was a no-brainer.