The Oppo brand of DVD players are said to be great as a transport, including the guy who designs great DACs and other gear (Dusty at Channel Islands Audio). The idea is that the transport/dac combo allows one to upgrade just the DAC part as one can afford better gear. With a standalone player, you get what you get unless you want to spend the extra money to modify. Jitter arises as a prime issue with a transport/dac vs. a standalone player which has less inherent jitter as the signal path is shorter and more direct.
The reason that a player is a lot more is that you are paying for all the engineering that goes into the thing from the transport mechanism, power supply layout, clock, dac, analog section, the case, the buttons, and controls, etc. However, it's also a fixed item that has limited upgrade potential and you know we all want to upgrade--sooner rather than later.
Splitting it up might actually yield more for your money if you catch the "upgraditis" bug.
OTOH, a transport, as a "platform", can then be the basis upon which one can continuously upgrade the source over time without completely getting new equipment. The main reason is that as technology improves semiconductor chips, the price/performance of a DAC gets better and better. You can keep your same old transport and get a totally different (hopefully better) sound with a new dac.
Right now, many people use their computer and swear by it as a superior transport vs. a DVD or cd player due to the negligible jitter from the USB signal. Given the amount of music that can be stored on mulit-gig hard drives, it makes for a strong case to just start with a computer if you don't already have a transport.
I'm about to start that given the the ability to manage all my music by genre, group, album, all through iTunes. When I'm on a rampage, I can just point and click rather than have dozens of cds and jewel cases strewn about the room after a night of smoking, drinking, and rocking. When you throw in the ability to upsample, EQ, and in general fiddle with your audio stream through software, the convenience and features of a computer-as-source blows away the old cd or DVD player platform. Too bad I'm too stubborn to really change over to it, but I'm as close as I've ever been.