You also may want to consider making your primary key ID column non-clustered and define your clustered index on a more suitable column, eg. a record timestamp.

Queries involving a *range* of values on a certain column/columns, such as a datetime range, benefit greatly from a clustered index defined on that column/columns.

Defining your PK as non-clustered means that page splits due to table UPDATES will NEVER happen - an update of a varchar column will not affect the stacking of the PK pages.

Personally, I find that defining an identity column PK as clustered is wasting a precious resource, unless this is the ONLY index you think you will EVER need on that table.