Possible Duplicate:
What is the difference between List (of T) and Collection(of T)?
What is the best practice for when to use one vs the other?
Both implement IList<T> and hold the data in an ordered fashion, but only List expose the sorting semantics....
Collection<T>:
Provides the base class for a generic collection.
List<T>:
Represents a strongly typed list of objects that can be accessed by index. Provides methods to search, sort, and manipulate lists.
So, according the docs, one is intended as a base class for collections. The other is intended for use as a container.
So use List<T> and inherit from Collection<T>.
