Suggestions

Short answer: there is no “best”.

what’s your budget?

Need to know what speakers and/or source?
Do you like warm and tubey?

BUDGET $2500-$3000 SPEAKERS ARE OLD JBL 4320S

These VTA M-125 monoblocks would be a good option:
http://https//www.audiogon.com/listings/lisa6i1j-vta-m-125-mono-tube-power-amplifier-pair-bob-latino-tubes4hifi-m125-29698-tube

Or, if you want to stay with C-J, here’s a nice MV-55:
http://https//www.audiogon.com/listings/lisa6hc0-conrad-johnson-mv-55-tube

although, I would say you already have a great tubey sound with your preamp, so why not save yourself some money and go solid state?
http://https//www.audiogon.com/listings/lisa6gbe-conrad-johnson-mf-2200-solid-state

The horns ask for tubes or class A. 
16 ohms also ask for tubes.
However, you need a lot of power, minimum 60 wpc.  That rules out a lot of tube amps.