I'd recommend the RV60, which has a built in DD 5.1 decoder, but it seems only the RV80 has both DD5.1 and DTS... the RV60 specs list it as having only DTS Out. I have no idea what the price difference would be, other than in Canada the RV60 is about $100 more than the RV30, and their site-posted MSRP says the RV80 is $100 more than that.

At those prices, I don't think it's worth it. I'm sure other units include BOTH for the one lower price.