I am a big Raytheon 5687 fan. When I had the SWL 9.0 I had some 1955's that were just fantastic as well as some versions from the 60's.
I am also a fan of the Philips production (dutch made)metal base GZ-34/5AR4. I have early fat base (f-31) as well as older versions of the Mullard (UK made) GZ-34/5AR4 and they are pretty good as well. I just prefer the Philips metal base. (Philips, Mini Watt, and others)
You can't go wrong with the Tung Sol 5687.......not as nice as the Ratheon's ,IMO, but it is a great 5687. (They invented the tube)