This is the most commonly asked question about SCCM . Well the answer to this is :

Policyagent.log : This log contains information about the new policies received by the client.

Policyevaluator.log: This log contains information about the evaluation of new policies that are being received .

Datatransferservices.log : This log contains the software download information onto the client machine .

execmgr.log ( Most Important) : This log contains all other relevant information .