I have done all of my Flash applications up until now with the Flash IDE (although I rarely use the timelines, since I prefer to do everything in code) or in FlexBuilder as Flex applications. Are apps that just extend Sprite (used in the FlexBuilder IDE, for instance) a viable way of doing an application, or are they just for HelloWorlds? Under what conditions would you not bother to use the Flash IDE? Can MXML files be used with apps that just extend Sprite?
Note: I'm not asking when to use Flex vs. Flash. I am also not asking whether the Flash IDE or the FlexBuilder IDE is better for editing ActionScript files.
Edit: What I mean by "can MXML files be used with apps that just extend Sprite?" I am referring to whether you can use MXML markup in an Actionscript 3.0 file in Flexbuilder 3. I'm pretty sure you cannot do this.