I run both in both my systems, the AppleTV is cool for a convenient music server, but as the above poster said, it is only 720p. Blu-ray will give you 1080p AND uncompressed audio. The difference between DVD/AppleTV and BLu-ray when it comes to audio (even in two channel) will be significant.
I would recommend both but if you can't swing both at this time the Blu-ray player will give you more performance for the $$.
I would recommend both but if you can't swing both at this time the Blu-ray player will give you more performance for the $$.