Good examples of value types

[via Digitalmars-d]

Hi,

For a comparison with the Java language, I'm trying to come up 
with some good examples of custom types that should be value 
types (but that must be ref types in Java). I think the most 
obvious ones are numeric types. So BigNum, MyNum, etc. are good 
examples because programmers are used to numeric types being 
value types, and having them suddenly become a ref type just 
because it's MyNum instead of long is really annoying. Still, 
could you come up with some type that would really benefit from 
being a value type but that isn't numeric (or otherwise similar)?

Thanks for your help!

Luís