My internal sound card is an Asus Xonar Essence ST. At the time that I bought it, the newer STX was out already. However the ST did have some better components compared to that later model so I decided to get the ST.
I also have its companion expansion board, the Xonar Hdav H6 board making this a 7.1 Xonar Essence ST Deluxe setup.
Over time I may look into more modern multichannel DAC’s but I must say I’m still very content with this multi-channel sound card as the base for my multi-channel DSP setup. I use all 8 channels within the processing chain but only 6 outputs are currently in use. That leaves me with 2 more channels to play with for future experiments!