I am usually very reluctant to give recommendations on audio gear since perceived performance is so dependent on listener preferences, associated gear and listening environment. However, the LS25 MKI, with NOS 6922 (6H23), is a very musical and transparent performer. Coupled with the ARC VT100 mkII the LS25 MKI produces a huge, coherent and transparent 3D soundstage, with excellent dynamics and articulation. At about $2000 used, it is hard to beat.