Given the option, I go with DTS over Dolby. As gonk noted, the conventional wisdom is that it's the sonically superior format because of the higher bitrate and less aggressive compression scheme. DTS is typically 754kbps but can go as high as 1509 kbps By comparison, DD 5.1 operates at 384kbps or 448kbps. With that, comes a slight edge in frequency repsonse with DTS. However, I understand the higher bit rate is a real bandwith hog and can impact available space for video and special features.

There's a great website devoted to DVD formats that has a very thorough explanation of the differences: http://www.spannerworks.net/. Here's a quote from the site that summarizes the sonic differences between the two (and may spark an interest in further reading):

"Even though there are no compelling technical grounds for believing DTS is a better system, there are times when the DTS version of a soundtrack does sound considerably better than the Dolby Digital version. This can almost certainly be attributed to the way in which the DTS version has been mastered, although the DTS system itself cannot be discounted as a contributing factor. DTS titles often utilise higher quality masters and do not require alteration for optimised downmixing. These factors alone makes DTS worthy of serious consideration from an audiophile perspective."

Spannerworks also has up to date lists of all DTS encoded movies.

- VD