Help in putting together my system with used equipment on Audiogon and eBay.

I can describe my system built on used/vintage components to give you an idea what you can do for few thousand dollars with used equipment.

Speakers: Polk Audio SRS 1.2TL - Yes, Polk but it’s from Polk golden years and true monsters. Mine have almost been totally rebuilt with higher grade crossover components and tweeters than original. I built new crossovers with all new components. Cost maybe around $3000 with upgrades. Many think these speakers are about volume but their true strength is the sound quality and imaging (at all levels). I also have a sub and I would recommend something like an SVS SB-3000 if your room is big.

Amplification: Combridge Audio Azur 851W - This amp delivers 200 wpc in 8 ohms and 350 wpc in the 4. The SRS 1.2TL should be around 4 ohms after the crossover upgrade. Plenty of power. Biased towards class A but runs a bit hot though. Got mine used for about $1000. My original plan was to power the SRS 1.2TL with something like a pair of Parasound JC1 monoblocks or a single JC5. Until then the Azur 851W works just fine.

Preamp-DAC: NAD M51 - Smooth and natural sounding DAC that can be used a preamp. Plenty of inputs. Got mine for about $1000 two years ago and can probably be found for less today. I might have opted for the CA Azur 851N preamp/dac/streamer to match the power amp but like the NAD so much I don’t wan’t to bother.

Streaming: Chromcast Audio & Rasberry Pi with RoPieee image for Roon. Cost almost free. :)

I think what I have hoarded sounds pretty amazing but with $8000 you should be able to get components that are considered more "high-end" than mine. :)

The possibilities are endless! I’d focus on the speakers first. You should have plenty of options if you’re willing to spend $4000-$5000 on used speakers ..802 Nautilus maybe.. Have fun!

I loved my B&W 804 Nautilus for a very long time and compared them with other speakers over the years. I did a trial on a pair of Tekton Double Impact speakers just to see what the fluff-up over Tekton was about. The 3K Tektons were a huge improvement over the 804s. I was so shocked and impressed with what Tekton was doing, I returned the DIs and purchased Ulfberhts. Those are out of your price range but I just wanted to relate this experience from a former, huge B&W fan. Tekton has a free trial period and will only require return freight. They are also extremely efficient and will certainly get loud if that's your thing. I built a Pass B1 Korg preamp and a F5 power amp. The Tektons love Pass too when fed from my turntable. After a long period of trial amplifiers/DACs/etc, for digital I chose a Lyngdorf integrated amp that includes an excellent internal DAC. So you would save the money for that. Just food for thought from my personal direct experience with this hardware. Not rumors on the internet. https://www.tektondesign.com   https://lyngdorf.com/

As the Small Faces song says
" I wish that I knew what I know now when I was younger "

Since you are starting from scratch I'd recommend a tube or hybrid integrated amp , you'll save a lot by not by not having to spend money on interconnects and power cords . 
You have CD's and used ones are very cheap ,
CD players and their DAC chips have come a long way .  
I don't recommend jumping into Vinyl at first , something you could get into if you really love spending time and money on your hobby .
As for speakers , I'd say read Audiogon forums , 
read older copies of The Absolute Sound and Stereophile .

I have Thiel speakers so check out the Thiel Owners audiogon forum .

Good Luck and Happy Listening

I'd work with what you already have and not sell anything, because you'll lose money. That said, in building any audio system (other than a headphone system) you need to start with your room: assess your room and pick speakers that effectively drive your room. Borrow speakers from dealers or friends if necessary to learn what works in your room. I can't tell you how many great components I've heard playing into great speakers that sound like crap because they were not suited to the room. For example, do you need to place speakers near or next to a wall? Larsen, certain Klipsch and other speakers work better in those locations. Don't pick B&W because of reputation. Find out if they drive your room. Once you've found your speakers, get an amp that will drive the speakers. Fortunately a Bryston will drive anything, so you are probably covered there, going backwards to the source component. But whatever you spend on the front end, it won't matter if your speakers don't sound good in your room, which is a much greater variable than the difference between amplifiers from Brand A and Brand B. 

Hi, your brain will hurt before this thread ends!  So many opinions and a broad question.  My thoughts:
1) you have a great pre amp; so stay with separates and wait on amp purchase until you know your speakers and have listened.  It's easy to wrap your head around how speakers compare in any given environment than it is to find the right amp to speaker combination.  So for that I like to hear advise and recommendations... I like a warm SS amp like my old Classe CA 2300 or the hybrid sound of the PS Audio BHK.  I have not heard a lot of Pass but everyone seems to love them.  $$
2) I have happily ripped my CD's, started streaming, and then bought a nice DAC and never looked back.  Vinyl (to me!!!) is as much about the experience of choosing, cleaning and cueing up an album...and chilling and listening.  Bad digital is bad, but it can get quite good (to me!).
3) I have both a PS Audio Direct Stream and an Auralic Vega G2.  They sound great with my Roon Nucleus and separates.  Again, vinyl looks and is cool and I keep thinking about it..but it would never be my core listening, just a fun thing to play with.  (flame away!).
3) People love to trash B&W.  I have had two sets of the original Nautilus 802's and they are awesome.  I have auditioned all the successor 802's. Diamond versions (?3) and the newest.  Somehow I think they got less smooth, more analytical sounding and less attractive.
But I like cars from the 60's.  You can get the 802N's for a great deal I agree.  I paid $4200 for mint ones two years ago.  They can be very revealing, and love a warm environment (carpeted basement!) Mine are staying.
4) I also think the Revel Ultima 2's either the Studios or especially the Salons are a great used value.  They are so smooth and calm and easy yet everything is there.  But so many choices in speakers and how they look in the room etc.  Ive been told pretty cabinets means less focus on the components but I think why not be beautiful as long as you like the sound?  I did audition and pass on the most beautiful Italian ones...
5) a couple of years from now, when everything sounds perfect, audition some nice power cables or interconnects from the Cable Company.  For a deposit and the price of shipping, its fun and educational.  I did not want to believe it could make a big difference, but in my systems and to my ears, upgrading my main power cables (conditioner and amp) and interconnects (Two sets XLR), made significant improvements.  They let you try the cables for two weeks, so easy to hear for yourself. Good Luck!  Ken