Rounding SQL DateTime to midnight

I am having a small problem with my SQL query. I'm using the GETDATE function, however, let's say I execute the script at 5PM, it will pull up records between 12/12/2011 5PM to 12/18/2011 5PM. How can I make it pull up records for the whole entire 12/12/2011 - 12/18/2011 basically ignore time.

My script:

WHERE Orders.OrderStatus = 'Shipped'  
AND Orders.ShipDate > (GETDATE()-6)  

In SQL Server 2008 and newer you can cast the DateTime to a Date, which removes the time element.

WHERE Orders.OrderStatus = 'Shipped'  
AND Orders.ShipDate >= (cast(GETDATE()-6 as date))  

In SQL Server 2005 and below you can use:

WHERE Orders.OrderStatus = 'Shipped'  
AND Orders.ShipDate >= DateAdd(Day, Datediff(Day,0, GetDate() -6), 0)

Here is the simplest thing I've found

-- Midnight floor of current date

SELECT Convert(DateTime, DATEDIFF(DAY, 0, GETDATE()))

The DATEDIFF returns the integer number of days before or since 1900-1-1, and the Convert Datetime obligingly brings it back to that date at midnight.

Since DateDiff returns an integer you can use add or subtract days to get the right offset.

SELECT Convert(DateTime, DATEDIFF(DAY, 0, GETDATE()) + @dayOffset)

This isn't rounding this is truncating...But I think that is what is being asked. (To round add one and truncate...and that's not rounding either, that the ceiling, but again most likely what you want. To really round add .5 (does that work?) and truncate.

It turns out you can add .5 to GetDate() and it works as expected.

-- Round Current time to midnight today or midnight tomorrow

SELECT Convert(DateTime, DATEDIFF(DAY, 0, GETDATE() + .5))

I did all my trials on SQL Server 2008, but I think these functions apply to 2005 as well.