valgrind took the world by storm, making it really easy to find memory errors and profile your program's performance. Solaris's DTrace is the killer advance of the last few years. Similarly, Firebug has become a must-have tool for web developers.
X-develop, and its little brother CodeGuide, are commercial IDEs that are developed by Omnicore and respectively sell for $499 and $399. CodeGuide includes Java support, while X-develop also supports C# and Visual Basic on .NET and Mono. What sets them ap