Oracle have just released a new visual SQL that is well worth a look. I'm big fan of
Toad, but you have to pay for it because the free version stops working after 30 days. Oracle's new tool is free, and everybody likes free stuff.
It does a pretty good job of all the standard stuff you ever need to do when working with a database and it has some nice visual tools and wizards. It's one big downfall is that it only works on version 9.2.0.1 and up of their database, so if you're running an older version you'll have to use something else. But overall it's a pretty solid tool.
Take a look at
Oracle SQL Developer for yourself.