It absolutely is. I recently sold mine because money was tight, but immediately it was useful for Netflix and streaming my iTunes library to my TV. It works much better than my PS3 did for that purpose and it was well worth the money.
If you have an iPad or iPhone and want to share something you're playing on that device that isn't on the ATV(ABC,NBC,CBS...things like that) then you can and then you can watch TV shows without really needing to have basic cable.
I have two ATV3's and would not be without them, absolutely love them. I wish there was a work around for NAS connectivity. I had ATV Flash on my ATV1's and miss being able to connect my ATV3 to my NAS. I just finished updating all the meta data on my movies & TV shows using iDentify and highly recommend it.