i would also recommend a dedicated cd player, although some highly praised universal players (the ayre for example) play everything but dvd video. the key is to listen & compare, & to make sure that the levels between the various players are matched. when i demoed a cary 300/303 cd player v. a cary dvd7 v. my cary dvd6, there were clear differences between the 3 players, with the 300/303 having a clear sonic superiority over the other 2 players, particularly on large scale classical pieces. for smaller venue jazz there was less of a difference, with the exception of the treble, which both the 300/303 & dvd7 besting my player my a wide margin. i once owned a denon 2910 but sold it after i bought my dvd6. have also demoed twice a 5910 and didn't buy it, but i only evaulated the audio, as i asumed the video would kill my dvd6 which does not upscale video. the 5910 was a better audio player than my dvd6, but it was by a slim margin (even comparing sacd from the 5910 to redbook cd out of the dvd6), & one i was not willing to pay for.
the best redbook cd players i have heard in no particular order: the top of the line dcs player & dac, classe cd player, simaudio cd player, mcintosh 2 channel cd/sacd player, cary 300/303. from my listening experience & alot of home demos, a dedicated cd player can make a significant & worthwhile improvement in music quality.