Trulia Crime Maps

From the same SF dude who brought you Ratio Finder, TCM helps you decide where not to live using a year's worth of crime data in 50 metros (including SF) that the gizmo plots on a map, along with color-coded intersections based on the findings (green is good, red is bad). And wait, there's more -- it also lets you play around with 10 categories of illegality to find out where in SF you're most likely to be robbed, assaulted, or live among drug dealers, three wrongdoings you're usually on a 6th and mission to avoid.