I owned a 6650 for a long time (for me). (if it's the one I'm thinking, anyway) I know it sounds quite good for $2-300 or so but.... I don't know how capable it will be to really show off the differences between a $100 DVD player and a $1200 tubed CD player. I'd also look at the input and output impedances of the gear to make sure it's going to be a good match. It most likely will but, just a thought.
If it were me, I'd do a bit of a compromise.. maybe upgrade both the cd and the integrated at one time.
Or, I'd just buy one the well-reviewed dvd players and be happy you saved a bunch of money. I'd highly recommend a Pioneer 656a or 563. Also, the Toshiba 3950 is supposed to be great... And the Phillips you mentioned... I haven't heard those but the Pioneer's are better than they should be.
Alex at APL
www.aplhifi.com is supposed to be coming out with a modification for the 563 that will be tubed. You could buy the player now, then get it modified later.
Just some options. I'm not downing the HK, it's pretty good, as good as an Arcam integrated I had from the same time period... but not as resolving as others.
Have you considered any of the Chinese integrated?
-Carl