My personal favourite is the 4000/4002/4004/6000 series as the build quality is something else (try picking one of the AC models up!). There's also a lot to be said for the 8002 series, though I do not have one of these.
I have a 5005, and the build quality is not the same as my 4002, but it's still a sweet sounding (if a little bass light) deck, that has the advantage of being able to be connected via datalink to an appropriate Beomaster.
I suppose it depends on what you want to connect one to, as there will be RIAA issues depending on whether the amp/turntable you want to pair has/hasn't a RIAA pre-amp built in. It gets confusing here, so I'll let others step in.....
John
President, Beomaster 8000 Appreciation Society