DECLARE @b DATE, @e DATE, @cmd NVARCHAR(MAX)
SET @b = '2012-07-01'
SET @e = '2014-01-25'


SET @cmd = 'DELETE FROM DateTable
WHERE ValueDate BETWEEN ' + CONVERT(VARCHAR,@b,121) + ' AND ' + CONVERT(VARCHAR,@E,121)

EXEC sp_executesql @cmd

-- Only the WHERE clause changed:
WHERE ValueDate BETWEEN CAST(' + CONVERT(VARCHAR,@b,121) + ' AS DATE) AND CAST(' + CONVERT(VARCHAR,@E,121) + ' AS DATE)'

PRINT @cmd;

WHERE ValueDate BETWEEN ' + CONVERT(VARCHAR,@b,121) + ' AND ' + CONVERT(VARCHAR,@E,121)

WHERE ValueDate BETWEEN 2012-07-01 AND 2014-01-25

WHERE ValueDate BETWEEN 2004 AND 1988

SET @cmd = 'DELETE FROM dbo.DateTable -- always use SCHEMA prefix
 WHERE ValueDate BETWEEN @b AND @e;';

EXEC sp_executesql @cmd, N'@b DATE, @e DATE', @b, @e;

WHERE ValueDate >= @b AND ValueDate < DATEADD(DAY, 1, @e);

DECLARE @b DATE = '2012-07-01', @e DATE = '2014-01-25',
        @sql NVARCHAR(MAX) = N'';

SELECT @sql += N'
DELETE ' + QUOTENAME(s.name)
 + '.' + QUOTENAME(t.name) + '
  WHERE ' + QUOTENAME(c.name) + ' >= @b
  AND ' + QUOTENAME(c.name) + ' < DATEADD(DAY, 1, @e);'
 FROM sys.tables AS t
 INNER JOIN sys.schemas AS s
 ON t.[schema_id] = s.[schema_id]
 INNER JOIN sys.columns AS c
 ON t.[object_id] = c.[object_id]
 WHERE c.system_type_id IN (40,42,43,58,61);
       -- or just = 40 if you're only interested in DATE columns

PRINT @sql;
-- EXEC sp_executesql @sql, N'@b DATE, @e DATE', @b, @e;