Best Cartridges for the Money You've Experienced

I'd like to ask those of you who have tried many a cartridge over the years to nominate ones that you feel are among the very best and are available today, new or used, at a substantially lower price than most of today's reference-level cartridges. Feel free to mention great cartridges from years past that still show up now and then on Audiogon.

I currently have a Koetsu Rosewood Signature mounted on an SME-5 arm. I'd like to go up from there in sound quality without having to rob a bank.