Another vote for Flash. FlashIDE and Flex aren't the only options too, haXe (http://haxe.org http://haxe.org) is quite viable as well and has a lot of features

Another vote for Flash. FlashIDE and Flex aren't the only options too, haXe (http://haxe.org http://haxe.org) is quite viable as well and has a lot of features and flexibility that make it my first choice. With swfmill the graphics can be made as svgs.