DTS hands down!! Everyone can be polite and say it "depends" based upon whether the sound mixing engineer had a bad day or not, or give you the technical specs.. but over the years i have always used what I trust the most.. My Own Ears... I have heard more sounds and clearer definition of effects in the DTS versions of Gladiator and Saving Private Ryan..Go buy the movie Underworld.. 1st release was in Dolby Digital. 2rd release is now available in superbit DTS.. Columbia Pictures makes superbit dts recordings.. WWW.SUPERBIT.COM...More expensive version but you'll enjoy it all the more...The movie aside, I haven't come across a DTS version that I didn't like. Can't say that about Dolby Digital.. And to show my softer side.. there are some DD versions of movies that are not too bad, ie THX certified stuff like Star Wars.
Lastly..something to make u go hmmm... There will be a DTS format standard on all high defintion DVD releases. If DTS wasn't such a big deal.. Why not keep dolby digital as your standard for the next generation of dvd format? Manufactueres know, to get you to purchase old movies or new movies in the HD DVD format, they better have sound to boot!!