Given your budget, I would go with a BD player first. Panasonic offers good ones for very little money. If you don't want to replace the receiver, you will want to get one with internal decoding and multichannel analog outputs to be able to get the new audio formats. (And given your budget, if actual performance is what matters for your money, rather than convenience, I would recommend doing that instead of replacing your receiver, which is otherwise fine.) Then I would consider a subwoofer, or replace speakers (to improve them, or to simply get them to match each other more exactly, especially the front three should match).
And as for the subwoofer, I like SVS, and I don't think you need to worry about having ports in it. Buy based upon actual bass performance, not irrelevancies.
