Seems like a pretty decent line up that. Only, you really have to rely on the top order to score runs.
According to the Cricinfo stats, the tail (in my opinnion starting with Akhtar on 7) only adds 50(.26) runs in Tests. That makes an avarage of 12.5 per wicket. Pretty low I think.
ODI's are even worse: 29(.71) runs scored for the last 4 wickets. Mainly because Sreesanth has an ODI avarage of 1.40.
I couldn't be bothered to calculate the top order avarage, but this are the stats for the tail. I think this is a good line up, but there´s little margin for error. Everybody has to do their jobs, and do them pretty good too. If, for example, Sangakarra fails for just 1, I don´t think it´s likely the tail will compromise his failure with sufficient runs. Maybe add an allrounder at 7?