mp3 is the generic term for all portable digital music players, of which ipods are merely the most well-known, in the same way that Hoover is the most well-known vacuum cleaner. In other words, an ipod IS an mp3 player!
if you are buying an ipod get the 80gb one i have this one you can download music (likean mp3) but you can also store personal photos videos etc and also download music videos games tv shows and films from the itunes store
You can get mp3 /mp4 players with just as good specs as an ipod.. ipods notoriously tend to have faults with their batteries which are inbuilt, and there have been lots of consumer reports saying that their ipods die after a year, which Apple regard as a satisfactory life for the device!