What's a guitar that can handle both rockabilly & "classic" metal in your opinion?

[d_dave_c]

Rickenbacker 620 or 330. The hi-gain pickups can rock or twang with the best of 'em.

 

 

[Alecto]

I see you, and raise you by I. The Ultra III!

 

Damn, you best me to it!

 

Seriously though, this is an inspired choice if you want to go from rockabilly to hard rock.

[Fiveway]

This fella has the tone and attitude to be played by Reverend Horton Heat, Volbeat, Motorhead and Sabbath simultaneously.

 

[tedmich]

[Pine Apple Slim]

[Uma Floresta]

I'd just grab a black Gretsch - which model depending on budget. You could kick on a fuzz pedal and do Black Sabbath easily.