I suppose that would depend on what you're looking for? Collectability? Reliability? Sonics? Looks?
Currently, I have a Beogram 4004 and a Beogram 5500 (part of a complete white 5500 system).
I have in the past owned an 8000, 8002, and 1800.
There's no question that B&O threw the whole weight of their engineering behind the linear trackers, and so these, for me are the most desirable, best built, and best-sounding tables.
I sure would love to have the original Beogram 4000, the first of the linear trackers. Never available in the States.
Next up is a toss-up between the 4002/4004 successors and the next generation 8000/8002.
Personally, I like the looks the looks of the 4000 series better, and I would rate the build quality a scotch higher than the 8000. Of course, the 8000 uses the nifty eddy drive system, and is a bit newer--though either one will require service if it hasn't had it already. If you get an 8000 series, get the later 8002, which will allow you to use the MMC series cartridges.
After the 8000 series, the tables took a dramatic turn towards cost-cutting, easily noticed by the much lighter weight and correlating use of flimsy plastic. Still sound nice, and worth getting if you get a good deal that includes cartridge, but not on my list of "the one."
So the short answer, the "one" to have, IMHO would be your choice of:
1) Beogram 4000 series/Beogram 8002
It's a given that any B&O table requires the expensive and dicey vintage B&O carts, or the expensive and reliable Soundsmith alternatives. The thing is, those carts are really good, and of course, with the B&O, you're getting an integrated system, with the entire turntable, tonearm, and cart designed to work together...not so good for tweaky types to be sure.
