Primarily Firefox (19.0.02) because my collection of extensions offer (1) improved security online and (2) facilities to access, manipulate, and save information suitable to my work flow. Occasionally use SRWare Iron (but uninstalling old versions and reinstalling new ones is tedious compared to Firefox's easy updates), originally because I wanted to improve load speeds, but find no consistent advantage over the current FF. I never use spyware Chrome; and I am also very careful to avoid the spyware "features" in all Google services (FF security extensions really help in avoiding these). Certain commercial sites require I fire up IE (9.0.8112.16470).