Preamp Recommendations Welcomed

I am in the process of acquiring a Blue Circle BC22 amp, which will be upgraded to MKII status at the BC factory. I'm wondering what to do in terms of a "synergistic" preamp to go with the amp. The BC21.1 looks good and has received some very favourable reviews. Any others that should be on my short list? Other gear in system:

- KEF Q5 floorstanders
- NAD C541i CD player
- NAD C420 tuner
- Van den Hul D102 MKIII interconnects

I am leaning towards a tube preamp, and favour tonal balance, clarity and musicality.

Regards.