I have no clue either
I hope the multi-channel in supports DTS-HD later this year, if not we'll be forced to buy new receivers.
In any case its probably best to wait late next year or so when the formats stabilize(compatibility issues) and players go done in price.
If a DENON dvd-3910 costs $1,000 imagine what a high quality blu-ray player would cost, $5,000?
It's best to enjoy what you have in the meantime without spending to much and they upgrading later(you'll be able to save if you don't spend too much nowadays)