Good news for people with 'parameter sniffing' problems.
Although Ken Henderson gave us a nice solution some time ago for SQL Server 2000, SQL Server 2005 will support the OPTIMIZE FOR statement. Adding this to a query makes sure the plan is optimized for the value you specify. And when all else fails you can even force a particular query plan with the new USE PLAN statement. I'll try to give some examples as soon as I find some time.