Leaving behind the Commodore Amiga, My first PC ever was a DX-2 66mhz and I bought Ultima VII and Ultima Underworld with it.  Unfortunately it didn't have any sound,  so I went to the store and purchased the Creative SoundBlaster Pro card and my life was changed forever.
 
I've been a fan of Soundblasters since 92, just like I've been buying nothing but evga cards since 2003.
 
I still have the SoundBlaster Z but my Creative Inspire 7.1 sound system is dying.  First the center speak went, then the front two, now it's running on life support in passable "Stereo" mode.   The audiophile in me misses how 7.1 gaming sounded in the year I first got it.
 
Does anybody own a modern SoundBlaster or did you switch to evga's NU Audo? Maybe another?  Also what would you recommend for a good 5.1/7.1 sound system nowadays?

Still using the Soundblaster Z.  Have really not found a reason to upgrade from it.  Still pumps out good audio.  Maybe new speakers?

If you like your sound card then just buy new speakers.
Even if you buy a new sound card your going to have to buy them anyway.
Some examples:
https://www.pcmag.com/picks/the-best-computer-speakers
https://www.amazon.com/7-1-surround-sound-computer-speakers/s?k=7.1+surround+sound+computer+speakers&page=2
 

 
Holy wow!    That Klipsch 5.1 system is on sale from 999 to 421.89
 
Wish I wasn't on "budget restrictions" ;) right now or I'd be all over that
 

I recently added an EVGA NU Audio sound card, and overall I have been very impressed with the sound quality using my AKG Q701 Reference Monitor headphones. Not the hardest cans to drive at around 60 ohms, but hard enough. Plus they love power, and good power makes them shine.

Tweaked
I recently added an EVGA NU Audio sound card, and overall I have been very impressed with the sound quality using my AKG Q701 Reference Monitor headphones. Not the hardest cans to drive at around 60 ohms, but hard enough. Plus they love power, and good power makes them shine.

Oh that is one sweet pair of headphones.  Comfort is critical for me.   My difficulty is finding a "behind the neck" comfort pair.   I prefer a surround system but when married you often get told to "turn that down please" ;-) so a good pair of backup headphones would be great.

I have a 2.1 audio setup for my PC consisting of a Creative Sound Blaster X-Fi Titanium HD and 2 x JBL LSR305 + 1 x JBL LSR310S.

Go optical out of your PC ( Most motherboards Ive owned have it built in) to an external setup OR USB out.
Check out Schiit audio.
https://www.schiit.com/products?gclid=EAIaIQobChMIwLXelN3X6AIVF4iGCh3cTwF_EAAYASAAEgJB9_D_BwE
 
Go to a DAC and then to a good pair of powered speakers, KRK are pretty great and well priced.
https://www.amazon.com/KRK-Classic-Professional-Powered-Monitor/dp/B07XZZTZ3Q/ref=sr_1_3?dchild=1&keywords=krk&qid=1586311138&sr=8-3
 
BUT for 5.1/7.1 the Creative stuff is pretty good still with the use of SABRE DACs. AE-7 has everything under the sun.
 
 
For a cheap/solid sub POLK makes a pretty solid unit for 99 bucks. 
OR if you go the KRK route, they make their own.