Whats your blockchain btc address?
And yes difference could be due to "change address" but i am wondering why its showing 0 balance.
1WrEg1Ls7AsbfLBDWuMzFkA2KEYcEWUgY is the blockchain address (or more precisely, the one it tells me is mine, 1MxuKm4jdpGqpUSJRE45gbanGsePEkRJnq is the one I've used to receive coins for a long time now.)
What's "change address"?
By the way, blockchain shows I have 1.4862583 whereas the client says 1.53337621. About a $35 difference at the current exchange rate.