You want a serious home theater. One that will rattle the windows, and ensure movie night is always at your house. But you don't want to spend more than $600 on the thing that ties it together. Cuz you're smart.
You've got the big screen flat panel, you've thrown that cheap HTIB system in the garbage, and you've picked out an awesome speaker system. You just need one more component to tie it all together: a surround receiver with enough muscle for Aliens vs. Transformers, and enough ports to handle your Blu-ray player, Xbox and/or PS3, and all of the other black boxes in your living room.