Looking for a new surround sound system.

So about 3 or 4 years ago I got a hi-fi system. 5.1, it cost me like
Flight Simulator and other chat
https://forums.simviation.com/phpBB3/
https://forums.simviation.com/phpBB3/viewtopic.php?f=9&t=27045
My computer has got 6 connections (green, pink, blue, black, orange and grey). The pink is the microphone and the blue is apparently another Line In, but that leaves me with the Green, Black, Orange and Grey. My current speakers have black orange and green input, but I have never played around with that and just used green.
I remember the days when we had some rather powerful speakers and we played the Top Gun intro through them full blast... You could certainly hear that outside the house! Excellent times, lol.
My previous speakers were really cheapy ones after the Christmas sales but they were very naff. I think all the digitally bits of the ones I am looking for are going to make it more expensive, just the S/PDIF connections and all that.
But that's what Christmas is all about, right...?