Best approach to remove time part of datetime in SQL Server

Question

Which method provides the best performance when removing the time portion from a datetime field in SQL Server?

a) select DATEADD(dd, DATEDIFF(dd, 0, getdate(         


        

Answer 1

SELECT CAST(FLOOR(CAST(getdate() AS FLOAT)) AS DATETIME)

...is not a good solution, per the comments below.

I would delete this answer, but I'll leave it here as a counter-example since I think the commenters' explanation of why it's not a good idea is still useful.