In Oracle, client tools are painful. You need to buy TOAD for a GUI, and has some good features (CTRL-Clkick to get table info) but it's basically a dogs breakfast.
SQL Developer is a free GUI by Oracle that pretty much does all that is needed - also, web based OEM is pretty good and offers stuff I have not seen in any other GUI like the capabiltiy to run and check AWR reports, real time tracing, etc.
TOAD is pretty bad at closing connections, I know production environments where it has been banned.
If looking for a third party GUI I would go with DBArtisan.
Pablo (Paul) Berzukov
Author of Understanding Database Administration available at Amazon and other bookstores.
Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.