Well if I was in your position I would skip the center speaker and put all the money into the mains. I think in that price range a phantom center is going to be just about as good. Plus the difference between $200 and $300 mains would be significant enough that I would go without the center. And in the $300/pr price range I would probably go with the Ascend CBM-170 SE which are on sale right now.
If you don't want to go that route, then the Athena speakers would be a good choice though I would suggest the LS-300 towers over the bookshelves, which with the matching center would come out to $300.