You did not specify the platform in which you are working. If you are on Windows, then Keil Development suite is something I found very good. However, CrossWorks is a very good integrated development environment. The Crossware ARM Development Suite is a sophisticated environment and is something you can try.
If you are on Unix platform you have Arm Compiler Toolchain might help. You can also try eCos. For more details on eCos visit Building the ARM development tools for Linux