Problemas SELECT em 2 tabelas diferentes (repeticoes)

Olá a todos!!!

Estou com um problema ao selecionar dados de duas tabelas diferentes.

As tabelas sao:

Tabela [CONTAS].[dbo].[t1]:

[t1.valor1]_ [t1.valor2]_____ [t1.datetime]

2__________ 1__________ 2012-08-21 10:17:28.933

2__________ 2__________ 2012-08-21 10:17:36.460

2__________ 3__________ 2012-08-21 10:17:38.997

2__________ 4__________ 2012-08-21 10:17:40.917

2__________ 5__________ 2012-08-21 10:17:42.230

2__________ 6__________ 2012-08-21 10:17:43.393

2__________ 7__________ 2012-08-21 10:17:44.703

2__________ 8__________ 2012-08-21 10:17:46.210

2__________ 9__________ 2012-08-21 10:17:47.493

Tabela [CONTAS].[dbo].[t2] :

[t2.valor1]_ [t2.valor2]_____ [t2.datetime]

1__________ 10__________ 2012-08-21 10:18:43.507

2__________ 20__________ 2012-08-21 10:18:47.187

3__________ 30__________ 2012-08-21 10:18:50.493

4__________ 40__________ 2012-08-21 10:18:53.587

5__________ 50__________ 2012-08-21 10:18:58.030

6__________ 60__________ 2012-08-21 10:19:01.287

7__________ 70__________ 2012-08-21 10:19:05.297

8__________ 80__________ 2012-08-21 10:19:08.837

9__________ 90__________ 2012-08-21 10:19:13.417

Gostaria de sempre selecionar as 5 ultimas linhas das duas tabelas.

Estou utilizando a query abaixo, porem os ultimos resultados da tabelas 1 estao repetidos (2 e o 9):

QUERY:

SELECT top 5 *

 FROM [CONTAS].[dbo].[t1],[CONTAS].[dbo].[t2]

	order by [t1.datetime] desc,[t2.datetime] desc

GO

RESULTADO:

[t1.valor1]___[t1.valor2]___ [t1.datetime]____ [t2.valor1]_ [t2.valor2]_ [t2.datetime]

2________ 9_ 2012-08-21__ 10:17:47.493_____ 9______ 90___ 2012-08-21 10:19:13.417

2________ 9_ 2012-08-21__ 10:17:47.493_____ 8______ 80___ 2012-08-21 10:19:08.837

2________ 9_ 2012-08-21__ 10:17:47.493_____ 7______ 70___ 2012-08-21 10:19:05.297

2________ 9_ 2012-08-21__ 10:17:47.493_____ 6______ 60___ 2012-08-21 10:19:01.287

2________ 9_ 2012-08-21__ 10:17:47.493_____ 5______ 50___ 2012-08-21 10:18:58.030

Eu nao consigo tirar essas repeticoes do 2 e 9 da tabela 1...help me!!

Se alguem puder me ajudar ficarei muito grato!!

Agradeco a atencao desde já... :)

Obrigado a todos!