MS SQL Server VarChar comparison strips off trailing spaces

While comparing two varchars MSSQL Server strips off trailing spaces.

Why is that ? Surely 'Hello' <> 'Hello '. Other whitespace characters, like TAB, don't seem to do this.

One option I found was to do a
SET ANSI_PADDING ON

But this does not seem to work for comparisons :-(.

Fianlly got the comparison to work by using the following line:

WHERE CONVERT(varbinary,field)=CONVERT(varbinary,@compare_value)

With grateful thanks to Joel On Software. Refer link : http://discuss.joelonsoftware.com/default.asp?joel.3.66884.22