To taste the cross-platform IDE for Rapid Application Development today:
http://www.lazarus-ide.org/index.php?page=whyuse
"Why use Lazarus?
No dependencies!
With Lazarus you can create programs which do not require any platform dependencies [1]. The result of it is the user of your program does not need to install any further packages, libraries or frameworks to run your software.
[1] Linux/BSD applications may depend on GTK2 or alternatively QT. Some add-on packages may also add dependencies of their own
Can be used in commercial projects
Some IDEs restrict their license to only non-commercial development. Lazarus is GPL/LGPL [2][3] which permits using it in building commercial projects.
[2] LGPL with additional permission to link libraries into your binaries. [3] Some additional packages come with various licenses such as GPL, MPL, ... "