miked,
i tink yule get the biggest sonic improvement by getting an audio-only preamp - probably tubed - and run all your audio gear thru *it*. it wouldn't surprise me at all if yer current cd-player, run thru a nice tubed preamp, would sound better than it run thru an outboard dac & the b&k. and, ya don't have to give up the h-t thing - many preamps now offer a default input for a h-t processor - chosing this input defaults all controls to the h-t processor, allowing the h-t processor to control the main 2-channel speakers, etc... vtl, sonic frontiers, adcom, linn preamps are like this, i'm sure there are many others.
doug