I use an EAR 859 with my AKG K1000s. I don't use them often enough though. While the separation between the binding posts is too wide (requires either jumpers or splitting the cable a bit...), I love the amp dearly. Despite its 13.5 watts, and the "headroom" offered by tube amps, I find the amp a trifle weak for true headbanging music. I can therefore heartily recommend either the 861, which gets an extra 1.5 watts (and the preamp section is by-passable), OR... the EAR 861 which has basically the same Enhanced Triode Mode circuit, with twice the power but without the preamp section.
Another I would love to try is the Pass Aleph Os...
Another I would love to try is the Pass Aleph Os...