FYR: https://en.bitcoin.it/wiki/Change
No worries, your bitcoin is safe and is in your change address.
Ok, great...that's something completely new to me. Thanks for sharing this link...But I think it's rather strange, that the wallet only shows one address and none of the change addresses.
So if I export my wallet from bitcoinQt, the *.dat file contains private keys for several addresses, right?
When I realized, that bitcoinQt shows another amount, than the wallet address holds, I tried to transfer the whole amount and I saw that the missing coins came from different addresses...so that makes sense now too.
Thanks a lot!