If you're willing to have one repaired/restored, then I'd recommend (US models):
Beogram 4002
Beogram 4004
Beogram 8000
Beogram 8002
I would consider the TX one step down from these, and the RX two steps down. But they're still good, so if you get one at a good price, it's worth it. The RX2 and TX2 are different, newer, and probably won't need nearly as much in terms of service as compared to a RX or TX, but are in general not quite as nicely built - B&O was anticipating the CD taking over when they designed these turntables. But a TX2 is still a fantastic-sounding machine, especially with a MMC1 or MMC2.
Beogram 4002
Beogram 4004
Beogram 8000
Beogram 8002
I would consider the TX one step down from these, and the RX two steps down. But they're still good, so if you get one at a good price, it's worth it. The RX2 and TX2 are different, newer, and probably won't need nearly as much in terms of service as compared to a RX or TX, but are in general not quite as nicely built - B&O was anticipating the CD taking over when they designed these turntables. But a TX2 is still a fantastic-sounding machine, especially with a MMC1 or MMC2.