When to use a HashTable
<p>In C# I find myself using a List, IList or IEnumerable 99% of the time. Is there a case when t would be better to use a HashTable (or Dictionary in 2.0 and above) over these?</p>

<p>edit:</p>

<p>As pointed out, what someone would like to do with the collection often dictates what one should be using, So when would you use a Hashtable/Dictonary over a List?</p>
