I am also in the preamp being the most important camp....it has been for me. The preamp has the most affect on the tone of the signal and when you get it right you know right away. In conjunction with that I have also found the cable connection that makes the biggest difference (although they all matter) is the preamp to amp connection.
Get those two things right and you are more than halfway there IMHO.
Get those two things right and you are more than halfway there IMHO.