Quality, Affordable, Preamps?

Ok, well quality and affordable maybe a subjective. I am starting to build a new 2 channel system. I have Adcom GFA-565 Mono's modded by Musical Concepts. Pre-Amp is a GFP-565 that I am looking to the area to start. CD is a Denon 2560 that will be replaced by a Rega Apollo I believe at this point. Speakers are Infinity Modulus. Nopt with the sub or the crossover cube. They made them sound terrible. I run an older M&K MX-2000 set at about 72 hz. I may replace the Speaker with PSB Stratus Golds or Maggie 1.7 sometime down the road. But for now I am looking for a descent Tube preamp. I know nothing about tubes. I was looking toward Mcintosh or the Musical Design Sp-2b possbly the new chemealeon. And would like to look at others just not sure where to start. New or used is good. Used maybe better might fit in the budget better. So, any input would be great. At some point it will all be upgraded.