How do I speed up deletes from a large database table?

Please see: Optimizing Delete on SQL Server

This MS support article might be of interest: How to resolve blocking problems that are caused by lock escalation in SQL Server:

Break up large batch operations into several smaller operations. For example, suppose you ran the following query to remove several hundred thousand old records from an audit table, and then you found that it caused a lock escalation that blocked other users:

DELETE FROM LogMessages WHERE LogDate < '2/1/2002'    

By removing these records a few hundred at a time, you can dramatically reduce the number of locks that accumulate per transaction and prevent lock escalation. For example:

SET ROWCOUNT 500delete_more:     DELETE FROM LogMessages WHERE LogDate < '2/1/2002'IF @@ROWCOUNT > 0 GOTO delete_moreSET ROWCOUNT 0

Reduce the query's lock footprint by making the query as efficient as possible. Large scans or large numbers of Bookmark Lookups may increase the chance of lock escalation; additionally, it increases the chance of deadlocks, and generally adversely affects concurrency and performance.

delete_more:     DELETE TOP(500) FROM LogMessages WHERE LogDate < '2/1/2002'IF @@ROWCOUNT > 0 GOTO delete_more

You could achieve the same result using SET ROWCOUNT as suggested by Mitch but according to MSDN it won't be supported for DELETE and some other operations in future versions of SQL Server:

Using SET ROWCOUNT will not affect DELETE, INSERT, and UPDATE statements in a future release of SQL Server. Avoid using SET ROWCOUNT with DELETE, INSERT, and UPDATE statements in new development work, and plan to modify applications that currently use it. For a similar behavior, use the TOP syntax. For more information, see TOP (Transact-SQL).

You could create new files, copy all but the "deleted" rows, then swap the names on the tables. Finally, drop the old tables. If you're deleting a large percentage of the records, then this may actually be faster.