I have always used TOAD by Quest to do my development and administration work in Oracle and MS SQL Server. However, I am trying not to be myopic in my choices. Are there other tools that you would recommend that will allow me to connect to the database(s) and perform my development and administrative duties?
I personally like MS SQL Server Management Studio to SQL Sever. SSMS 2008 is a very good improvement over SSMS 2005.
For Oracle (and MySQL it appears) you can use Oracle's free "SQL Developer", which being Java also runs on Mac OS X and Linux.
For PostgreSQL there is phpPgAdmin for an online solution, and the equivalent for MySQL. There are stand-alone applications like PgAdmin3 as well, but I haven't used them for a long time, having preferred the psql command line interface.
SqlManager.net have a range of tools for a cross section of databases. Also have a look at Altova's Database Spy
I've used TOAD before and wasn't very impressed. What I like using is Oracle tools for Visual Studio .Net . Their tools work within the server explorer within Visual Studio.
Surprisingly, phpMyAdmin. Not the fanciest tool around, but never failed me and it's already installed almost everywhere. I wish it supported more database engines than it's name implies.