Role of HDCD in an upsampling world

I am wondering about taking the plunge into upsampling players or possibly an outboard DAC.

My question is what will that do my HDCD discs? I have several hundred or so, and more on the way. These are some of the best sounding CDs in my collection and the music is nearly all of my favorites.

How can I best take advantage of HDCD and upsampling?

My system:

Arcam Diva 92

Rouge 99 Magnum (Sylvania chrome dome 6snt GTs)

Bryston 4B ST (Soon to be departed, likely for new Rouge Zeus)

Thiel CS 2.3

Cardas Golden Reference cables, PS Audio Lab II power cords, Power Plant, Ultimate Outlet, DH Cones and squares.

Thanks for this and all the advice in the past.