Much like hali, I have a preternatural dislike for Toad. There really is no valid reason for it, though, so I won't try to justify it. I just don't dig it. Equally unjustifiable is my preference for Oracle's own SQL Developer, especially now that it gives me a point-and-click interface for killing sessions. Well perhaps I can provide some justification in that Oracle SQL Developer comes packaged with ojdbc so I don't need to install anything else to run it other than the JDK. It's also completely free.