IF OBJECT_ID('tempdb..#source') IS NOT NULL DROP TABLE #source
CREATE TABLE #source (log_date DATE, NAME VARCHAR(30), VALUE DECIMAL(10,3))
INSERT INTO #source
SELECT '1-mar-2014', 'aaa', 100501.876 UNION all
SELECT '2-mar-2014', 'aaa', 100800.452 UNION all
SELECT '3-mar-2014', 'aaa', 100400.945 UNION all
SELECT '1-mar-2014', 'bbb', 104500.887 UNION all
SELECT '2-mar-2014', 'bbb', 100600.26 UNION all
SELECT '3-mar-2014', 'bbb', 100000.969 UNION all
SELECT '1-mar-2014', 'ccc', 100500.992 UNION all
SELECT '2-mar-2014', 'ccc', 100500.008 UNION all
SELECT '3-mar-2014', 'ccc', 100967.061 UNION all
SELECT '4-mar-2014', 'aaa', 0 UNION all
SELECT '4-mar-2014', 'bbb', 0 UNION all
SELECT '4-mar-2014', 'ccc', 0 

SELECT * FROM #source

SELECT log_date,MName,MaxValueForDate FROM 
	(
	SELECT s.log_date,s.NAME MName, s.VALUE MaxValueForDate, ROW_NUMBER() OVER (PARTITION BY s.log_date ORDER BY s.VALUE DESC) rowid
	FROM #source s 
		INNER JOIN 
		(SELECT log_date,MAX(VALUE) MValue FROM #source GROUP BY log_date) res
	ON s.log_date = res.log_date AND s.VALUE = res.MValue
	) final
WHERE final.rowid = 1	

SELECT TOP(1) WITH TIES *
FROM [Source]
ORDER BY RANK()OVER(PARTITION BY [log_date] ORDER BY [value] DESC);

WITH CTE AS(SELECT N=RANK()OVER(PARTITION BY [log_date] ORDER BY [value] DESC),* FROM [Source])
SELECT * FROM CTE WHERE N=1;