I (and a few other A'goners) have been quite happy with the (Polish) Circle Labs A200. It is a hybrid amp, but the two Siemens ECC8100 tubes last for ~10 years with normal usage, and require no biasing. You can read users' impressions here:
Also, a small note on the GATO Amp-150, which was recommended above. I owned one for a couple of years, and found it to be excellent. However, it features an active cooling system (i.e. a small fan), and while it was rarely needed, I did not like the added noise.