If it must be one speaker, then the 55Hz bass cone version of the G12H-30 is tough to beat.
In a 4x12, I like bass cone G12M-25s on the top and H's on the bottom.
Goodmans are nice, but they have a narrower voice coil than Celestions and don't take the abuse very well - I'm blown every Goodmans speaker I've ever owned.
Fanes can be great, but you need to match them with the amp - perfect with old Sound City and Hiwatts, not so much with Marshalls imo (though a VERY early Fane I have here for home use sounds great with anything, but then again its not 'classic' Fane in it's tonality).
Taydens are great from what I've heard and they did a great job of reconing my alnico Goodmans - they had a GREAT tone.