CodeWarrior for Symbian OS supports every stage of Symbian OS software development, from phone creation to 3rd party software development. It provides developers with a robust and easy-to-use integrated development environment (IDE) that provides all flavors of debugging for the various tasks of device creation and application development.
Nokia Developer's Suite for Symbian OS is a set of tools that enable efficient Symbian OS C++ application development using Microsoft Visual Studio .NET 2003 and Nokia SDKs for Symbian OS. Nokia Developer's Suite targets developers that have Visual Studio skills.
This article describes the plug-in for the Eclipse IDE that I've written which allows to write Symbian programs under Eclipse. It's quite simple (the lack of debugger is probably it's biggest drawback) but definitely nicer than running ABLD commands from the command prompt.