Dispose vs Finalize?

The finalizer is for implicit cleanup - you should use this whenever a class manages resources that absolutely must be cleaned up as otherwise you would leak handles / memory etc...

Correctly implementing a finalizer is notoriously difficult and should be avoided wherever possible - the SafeHandle class (avaialble in .Net v2.0 and above) now means that you very rarely (if ever) need to implement a finalizer any more.

The IDisposable interface is for explicit cleanup and is much more commonly used - you should use this to allow users to explicitly release or cleanup resources whenever they have finished using an object.

Note that if you have a finalizer then you should also implement the IDisposable interface to allow users to explicitly release those resources sooner than they would be if the object was garbage collected.

See DG Update: Dispose, Finalization, and Resource Management for what I consider to be the best and most complete set of recommendations on finalizers and IDisposable.