Why the credit scores differ?

I have recently pulled out my annual credit reports and I've got three different ratings with the three CBs. It has made me wonder since they all are showing same information regarding my finances. Wouldn't they be same? Also, how these differences in scores would affect my prospects of getting credit in the future?

It's simple really. The three bureaus use slightly different algorithms to generate scores. Although the information is (typically) the same, one CB may weigh one factor to be more slightly more significant than another CB. An example of one of these factors is "proportion of balances to credit limits is too high".