Martin Fowler writes about strongly typed collections, and concludes:

"On the whole, however, it isn't worth the trouble"  

I must admit that I disagree.  In anything but the smallest of projects it is both unconvenient and unhealthy to use untyped collections. Typed collections provide type-safety,better encapsulation and cleaner code. I would much rather invest 20 lines of code to inherit from CollectionBase than have explicit casts scattered all over my app (which are hard to debug and even harder to maintain).  And it is a good practice going forward because when generics become available (Whidbey) we will get all the advantages of typed collections for ~1 line of code.

In Martins defense, his code samples seem to be mostly Java so he probably means "On the whole, however, it isn't worth the trouble IN JAVA" and as we all know, nothing is worth the trouble of doing in Java ;)