The iPod killer is just like the World of Warcraft killer not gonna happen. THey both have way to much going for them. iPod- iTunes, already owned many and WoW- Dev team unlike any other involved in MMOs
There will never be an ipod-killer... people will keep buying ipods. There will, and has been, mp3 players better than ipods. Just look around. Ipods are their own equipment. It's always mp3 players, cd players, and ipods... Ipods aren't even listed under mp3 players, tho thats what they are, because they are so common and ----.
The iPod is merely a fashion fad, that is why so many people are concerned with the looks of other mp3 players. Had it not become such a fashion statement we would not being seeing the reactions we are. With that said the iPod is losing it's ground as Apple is no longer innovating, all they're doing is rehashing the same design over and over. Eventually it will lose it's appeal just as every fashion fad.