What can I recommend if I had to say a model?
It depends on what you want to do and what design of B&O you like. Age and faults is less important as you allready have found Beoworld. You can type in the unit in the search box and see what comes up. Typical questions, faults etc.
I began with Beosystem 2000 (mid 80's) by acident. Needed to be fixed but worked and sounded great for the next 3 years. I had the Beogram and Beocord. I had a discman plugged in for cd's. No remote or link option but one touch for whatever you would want to do. 7 pin data link was standard and worked great for the 3 units to connect to each other. Do not use Beovox X series speakers! They sound horrible! I can recommend it for not a very large volume room. On a technical side its simple for less experienced reapair guys.
Then I moved on to Beosystem 6000/8000. Everyone here says its classic for the BM8000 that came out in 1981. I had the Beocord 9000. If you are into recording cassete tapes this machine is B&Os Nakamichi. Playback is very good too but so is alot of other B&O cassete players. Belts go and lights drop out, DIN plugs get loose but owerall Beocords are the hidden gems as they sound very awesome with the right tapes!
Long story short. Beogram 8002, Beomaster 6000 in white, CDX cdplayer, white Beogram 6006 and Beomaster 8000 were all defective and serviced by Dillen here on site. Technically it takes somebody who knows what he is doing. Once its up and running its great. Sounds, looks and everything. It takes a bit of space. The BM8000 is more wide than a BM6000 so don't fit the normal B&O stands. The right ones are rare.
Beovox for these 6000/8000 are S/M/MS and usually rare without foamrot. Once fixed ready for 20 odd years or more. Great sounding as always.
The list of reapairs are long on my stuff. I knew Dillen's work, was on a budget but once there you get a really powerfull system in the BM6000 and BM8000. It can play loud and clear so it needs room for volume.
As it was mid '80s before a B&O cdplayer came out Beosystem 6000 and 8000 + 2000 were BM,BC and BG. A Cd can be connected like the CDX which is a great one and highly recommend anywhere but you loose remote option. Linking can be done for the 6000 and 8000. The parts are hard to find second hand. They do have their own remote which works great. On a BM6000 it was optional so not always in place but can be done.
I can recommend these systems highly too. Just be aware of who to do proper service when it needs it.
As I was moving into a big apartment with more rooms I was thinking how to link and finding the MCL82 units are posible but a Beolab kit is also needed and I have yet to even see one. One day last year there was a Beosystem 6500 online and since it was advertised with defective speaker outputs it did not go for high cost in the auction. A search here on Beoworld did no give this as a typical fault or at all.
Typical Timer out was what the Beomaster 6500 said. This turn the speaker outputs off. Simple fix as mentioned in the manual (download as silver or gold member) hold right and push left. That's it and it gave sound again.
I have been using this Beosystem 6500 nearly on daily basis since I got it. It came with the CD6500 and Beocord 6500. I found Beocord 5500 one day and its used as tape 2. Its got alot of options. I use it with MCL link so far to the kitchen. I got 3 2047 Xtra speaker kits and 1 tvkit to be put up. The AUX goes to the Beovision AV9000 through a 1611 converter and its really wonderfull to have the linking. You can control the system from every place in the house. You can even connect Beosystem 6500/7000 to the latest Beovisions made in 2010!
Remote wise you get MCP 65000, Beolink 1000, Beolink 5000, Beolink 7000 and Beo4.
The best amps are in the BM6000 and BM8000. The best options are in the late '80s early '90s such as linking and powerlink for Beolab speakers.
The sound of the Beosystem 6500 is great even through Beovox S series speakers. I personally use the Beosystem 6500 95% of the time.