i'd guess Abstract base should be reserved for "core" properties of the object
i guess Interfaces are there exactly so my displayThyself methods can be expressed.
Well,you mention that multiple inheritance is not allowed in C#,with Interfaces you can have multiple inheritane,you inherit a class from another class AND how many interface you want.
Serializable word express itself.It means you can seriallize this class. MSDN exapain these things very good,you can start from it.
No sig. available now.