You can still use it to stream DVD rips, BR Rips and music that you import into iTunes, you don't have to buy from the Apple store.
My PS3 works just fine for this purpose - I'm with Bwana - don't see the point of ATV. BTW, frontrow must be quite cool on a TV with the mini - sadly they are too pricy to justify as a media player - PS3 works for me.