I would recommend SQLDeveloper by Oracle. It has the same feature set as Toad, but is completely free. It can attach to Oracle, MySQL, and SQL Server simultaneously. I personally use the Express Manager for most DBA tasks, but SQLDeveloper is FREE and covers multiple databases.

The other nice thing is that SQLDeveloper is cross platform. I have it in Windows, on MacOS X, and Linux. It also runs well in virtual machines.

Bill