If you have very many DVDs, you'll probably find DD & DTS to be a fantastic improvement. And PL2 is much better than the original Dolby Pro Logic. You won't need to spend big bucks to get a decent receiver, either. There are nice entry level models for $200 or so, and you can get something really nice for around $500. A new receiver will have a lot of very convenient features too, like a remote that can control your whole system, plus video switching and a plethora of digital inputs (for a one-wire connection of CD players, DVD players, cable box, Playstation 2 & Xbox). The audio/video switching is particularly nice.