This Google Map mashup features about 18,000 Starbucks stores around the world. The map includes filters to find Starbucks stores with wi-fi, drivethrus, mobile payment and clover brewing. It is also possible to download all the data from the map in CSV format.
One reason the map is able to process so much data (and very quickly) is that it uses the SpatialDataBox. The SpatialDataBox provides a very economical way to manage the visualisation of millions of points on a Google Map.