Question: what guitars do opeth use?
Answer: Electric guitars: PRS Custom 24, PRS Custom 22 single cut, Fender Stratocaster A-standard, Gibson SG standard (modified), D'addario strings.
Bass guitars: Fender Jazz bass (Marcus Miller sign.), ... 
Acoustic guitars: ... 
Drums: ... 
Amps: ... 
Keyboards: Nord Electro, Nord Lead, both from Clavia.