Best 12at7 tube??????????

I was wondering what you guys thought some of the best 12at7 tubes are, and why? Please include guessed market value of the tubes as I'm doing a bit of a tube roll and could use some guiding information.
Thanks so much
I like the Mullard 6201 alot.
See Joes Tube Lore in the FAQs at AudioAsylum. Probably more than you ever wanted to know about 12AT7s.
The best 12AT7, I ever heard, was an RCA. Most RCA's sound lousy, to me. This just happened to be a pair, that was done right,(or wrong). They were the exact same construction, and vintage, as the others, that I thought sounded lousy. I still have that pair, today, and they still sound fantastic. If you want to tube roll, go out and purchase, some inexpensive 12AT7's, and listen, for yourself. Don't let someone else, tell you, what you like, or what sounds best, to you. What you will find out, is that a lot of tubes, sound great, just different.