Hi Jay,
I don't want to claim any special knowledge... but when I was around 6 years old in 1972, Ivor Tiefenbrun launched a product that is still in production: Linn Sondek LP12. The prevailing wisdom of the time was that "speakers were the most important component of an audio system." Ivor, much to the ridicule of just about the entire industry, challenged that presumption by claiming that "the source (i.e. turntable) was the most important part of a high-end audio system.
Over 100,000 turntables later, maybe he was right...
For all of you that may interpret this as a slam on digital, it is not. I am saying that once a signal is degraded, it can never be recovered so the better the source, the better the rest of the system has the opportunity to perform. So whether your choice is vinyl, digital, R2R or 2" masters (if you're lucky enough to have heard some of them) the ultimate high-end audio requires the best source you can buy.
I agree with @ron17: The less expensive your system is, the more likely you are to have to spend a disproportionate amount of money on speakers. Once you are into the moderate high-end audio range (maybe a $50K system) the balance skews away from speakers towards source, pre-amp (if you are using one), amp and as dramatically towards cabling and accessories. In my system, almost all of my components are msrp <$10,000 and my speakers slightly more, (I bought them used for only $4K). If you add up my cables/accessories (power chords, ethernet, interconnects, speaker cables, usb, isolation, power distribution), these have an msrp of around $50K! But if someone told me I had pick one component to "skimp" on reduce the value in my system. I'm sure I could be satisfied with an $8,000 pair of speakers.
I do not completely agree with Ivor. For me, a balanced system is the most important "component". It makes no sense to have anything disproportionately more or less expensive than the rest of the system. I'm sure the MSB Select would improve my system, but it would be just as silly to add it as it would be to add $100K speakers, unless I was upgrading the whole rest of the system commensurately. But as you go up to the "cost no object" system, I think law of diminishing returns hits speakers harder and faster than the other components so at Jays level, it comes as no surprise to me that the DAC is of primal importance.