One thing I often lament is the fairly poor collection support in the .NET framework. Sure, we have the workhorse classes like ArrayList and Hashtable, but we’re missing lots of other things. I big thing missing is a Set abstraction. I use Sets fairly frequently and I miss not having them built-in.
Thankfully, Jason Smith has implemented some Set collections in c# and made them available as source. I’ll have to go through these and turn them into CodeSmith templates so I can have strongly-typed Set goodness!