For me it's either the US or Great Britain, but I'll go with Great Britain because they produce the best bands.
Most Helpful Guy
With the USA and the UK, there is a "special relationship" musically as well as politically.
The blues musicians, sometimes obscure in the USA, definitely influenced a whole generation of British musicians, who in turn "invaded" America in the 1960's, and brought us Metal in the 1970's.
In turn, the UK punk rock left a very lasting impression on my generation, and for a time in the 1980s and 1990s it seemed almost mandatory for what were then called "modern rock" or "new wave" radio stations in the USA to have at least one DJ or announcer from England on their payroll, and ideally two or even three.0
Most Helpful Girl
For me its both.0