VW uses 57.1. Same as the Fiero. I belive the Dodge/Plymouth/Chrysler stuff is the same as well.
Subaru uses 56.1.
Toyota is quite a chunk smaller, but I don't remember what the measurement was, exactly.
All the applicable GM stuff is 57.1
Centerbores are usually not a show stopper if you're buying aftermarket wheels. Most but not all of them are huge (72mm?) and use the appropriate hubcentric rings. Just be sure to ask when you order your wheels.
VW uses ~35mm. Ideal (IMHO) for all pre 88 Fieros, and 88 rears.
Subaru uses ~48mm. Ideal (also MHO) for the front of 88s.