I have only had mine a couple of months, but following is what I have settled on:
white label, gold pin, Amperex 6922s
Sylvania 1952 3 hole bad boy 6sn7's (sometimes roll in TSBGRP but like the BBs a little better.)
Re-issue gold lion KT88s
Tung Sol NOS 5u4g
Of all of these, I would say the 6922's made the largest difference in sound quality - quite a jump in top end extension and dynamics / detail with these. Next the Bad Boys.
I have been using Proac Studio 140s but should receive some Silverline Sonata IIIs in a week or two.