Personally I’m more comfortable in AE building flashy (no pun intended) graphics, so I’d create something cool there first. Then embed the clip into Flash, which is where the interactivity is built. The whole thing goes out on the web as a SWF file. For the DVD loop used at conventions or whatever, just use the AE clip. Obviously there’s some amazing Flash artists out there, but I’m working on a piece for my company to use on screens at conventions that is all AE because I prefer it over the look of pure vector graphics. Everyone’s different so I’m sure there’s other opinions on how to go about it.
Steven