Thanks Steve for the question.
Thought I'd throw this in just for fun. Should work for every day of the year:
SELECT DATEADD(DAY, -DATEPART(dayofyear,GETDATE()),GETDATE())
The only problem with that is, since getdate() returns a datetime*, you're actually returning some time during the day on New Years Eve rather than the day of New Years Eve itself.
Of course, as of SQL2008R2, this still works:
SELECT cast(cast(GETDATE() as int)-DATEPART(dayofyear,getdate())-1 as datetime)
If you have SQL 2008 or higher and want to avoid questionable conversions, you could just modify your code thus:
SELECT CAST(DATEADD(DAY, -DATEPART(dayofyear,GETDATE()),GETDATE()) as DATE)
*depending on your SQL Server version