Dunno if they still make them but my old Dad used to have hundreds of old valves and he always swore by the one's that were made in the old USSR and Czeck Republic... 
(might be a wee bit hard to come by these days... 
Actually, my old manager at the previous place I worked was a radio enthusiast (in the technological, rather than the "ooh, that's a nice radio" sense). He bought several ceramic power amplifier valves rated at 2.5kW from some old soviet supply for the "moon bounce" competition (literally, bounce a signal off the moon and recover it).
These things were nothing like your common idea of valves of nice little glass envelopes with delicate coils and screens all lit up. They were big, heavy and had huge copper radiators on the top to which cooling fans were supposed to be fitted during operation. The looked more like sparkplugs from the devil's own internal combustion engine than a piece of precision (which they in fact were) electronics.
