A lot of people with ipods are unable to understand the concept of using anything other than itunes to transfer music. Dragging and dropping is even beyond some (I’m serious, I am unfortunately a lot of people’s first call when they have any kind of technology problem). So I think the ipod vs sansa issue goes well beyond aac support. I honestly think most people that rip in aac just do it because it’s the default in itunes and they don’t even think of changing it, or even know how to.
Obviously there will be people that this doesn’t apply to, just my experience.
iPod does seem to be becoming the generic term for mp3 players, which I really don’t like. However, in terms of ease of use, the ipod is still something I recommend to people who aren’t intuitive with computers/devices. So while I more than likely wouldn’t buy another one myself (but would by another sandisk product), I think there is a lot more to winning over ipod users than just aac support.