I did a few demos in the spatial visualization talk at SQLConnections using the AdventureWorks 2008 data. The Person.Address table is all geocoded and so I did a quick map in SQL Server Reporting Services 2008 R2 using individual addresses. Followed up later in the talk with addresses using ESRI's MapIt product, their Spatial Data Service and nice Silverlight controls. Both demos were projected over maps; I used both Bing Maps and a simple ESRI ARCGIS Server map.
As I zoomed and panned over the maps (SSRS 2008 R2 can zoom and pan during design time; ESRI controls allow interactive zoom and pan) some folks in attendence noticed that the street addresses from AdventureWorks 2008 don't correspond to "real" street names. Other folks told me they had problems using other geocoders with the AdventureWorks 2008 data.
The reason is pretty simple. Although the geocoding gets you to the right city/state, the actual addresses are "fake", aka, test data. So don't expect perfect street correspondance with real streets and test data. And…no, it's not a bug in your geocoder.