You could bridge stereo in order to create a poor man's 3.0 system.  Left, Right, and Monotone center.  Add a low pass filter to the center, and connect it to a subwoofer, and now it is 3.1 channel without any special encoding or software required.
 
Can't get much cheaper.
 

 
Add low pass filters, high pass filters, and amps as necessary.
 
 

Went from Logitech 5.1 to an AudioEngine 5 setup (2.0). So much better in every way that I never bothered to get an actual subwoofer. 
 
Whatever you get, I recommend avoiding Logitech. 

jfw06013
 I have these and love them
https://www.klipsch.com/p...ified-computer-speaker

He asked for a 3.1 system. Not 2.1.

jfw06013
Check this out:
https://techreviewpro.com...ile-computer-speakers/

He asked for a 3.1 system.

You could use an audio interface like the Focusrite brand, couple that with a pair of studio monitors. It would sound better than the "computer" branded speakers out there. I do have a set of Bose Companion 20's for one of my setups, but only because there is not room on that desk for anything bigger. However, I was VERY surprised at how well they sound for how small they are. I'd say they probably beat almost anything that you are going to see branded for "computers". The bass is actually very good. I mean very good NOT just for their size. However, as with any Bose product, you do need to EQ them to bring down the lows. For some reason Bose thinks they need to tune their products to have more bass... Luckily with a good sound card you can fine tune them.

The Klisph sounds even better when paired with the NU Audio.

I'm thinking a 2.1 set up would at least have a whole lot more options to look through compared to a 3.1 system. I have a logitech 2.1 system of the Z623. but I haven't done a whole lot with trying different speakers, so I couldn't really recommend a lot.

forrestang
There are definitely more options for a 2.1 system.

As I have shown, turning a 2.1 system into a 3.1 system is trivial. Add a speaker. Done. It's just one more speaker and 2 wire connections.
Just as it is very easy to turn 2.0 into 2.1, 3.0, or 3.1. It's simply hardware. No software or codecs required.
2.0, 2.1, 3.0, and 3.1 are all based on stereo. It's only when you go higher that it becomes more difficult due to surround encoding.

forrestang
Thanks for the suggestions all.
 
I had not thought about a 2.1 system, but it might be ok... as I'm not really an audiophile, I mostly just want 'ok' sound for my PC.  SO much so that i never bothered hooking up my rear channels for my current system.

If you were an audiophile, you would probably be looking at an expensive set of reference studio monitors and not 3.1. The middle speaker really isn't needed, unless you are buying a home theater setup. If you are just gaming, the setup you chose is going to be fine. I would also look at a good set of headphones, which I assume you probably already have.
 

forrestang
Almost ashamed to tell you guys what I wound up going with, but I think it will serve my purposes just fine. There are definitely more options for a 2.1 system.
 
The only thing I really don't like is that it has a silver base.  It bothers me enough that I might paint them. 
 
I do appreciate the bass knob that can actually turn the bass COMPLETELY off.  My older logitech, even when it was new... the bass was just always over powering on the lowest setting.
 
 Again, thanks a lot fellas, the advice was a BIG help.
 
https://www.amazon.com/gp/product/B007PXV2KM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1