The center speaker, as usual, will likely be the most important of the three so I'd try to get the best one possible. For $375 I think the Paradigm Monitor 7 Center 1 could be a very good choice, and you can pair it with the Mini Monitors and still be under $1000. I suppose you might get away with the Atoms and save a couple hundred bucks if you really have to, but I wouldn't.
As for the receiver, at this level I wouldn't sweat it too much -- just make sure you get the features and connectivity he needs (both now and for the future as much as possible). I'd recommend getting a model with room/speaker correction if at all possible. I like Pioneer and Onkyo, although I do see reports of people having issues with Onkyos from time to time.
Hope this helps, and best of luck.
As for the receiver, at this level I wouldn't sweat it too much -- just make sure you get the features and connectivity he needs (both now and for the future as much as possible). I'd recommend getting a model with room/speaker correction if at all possible. I like Pioneer and Onkyo, although I do see reports of people having issues with Onkyos from time to time.
Hope this helps, and best of luck.