I've had some great pre's, but my fav' was actually a vintage peice. Dynaco PAS-2, mine came with the original telefunken 12ax7 tubes and it was just plain sweet, literally as good as other new tube pre amps I had auditioned, I mainly used it for LP transfers of quadraphonic recordings. The circuit topology is what most modern tube amp manufactures use as a basis for their designs. One caveat, make sure you get a factory built unit, they were also sold as kits, though I have seen some of the kits built by audiophiles with pure silver point to point wiring, pretty nice!
As far a tube amps go, not much has changed in the last 40 years. But buy two older McIntosh monoblocks and you have an investment in your sound with as good or better quality than todays amps. When you want something new years down the road and you sell them you'll at least double your investment instead of losing 50% to depreciation.
my$.02
peace, chris