Why hasn't the Bitcoin client advanced to version 1.0? Who would invest money in a currency, which is held together by some software, which is currently in version 0.3.24? It is like putting ones money in a bank, which is currently undergoing in a test phase.

What is the rationale behind the decision not to go to 1.0? Obviously the incentives to break the security and steal all the money are there and have been there long enough for it to be deemed secure. I cannot even judge from the homepage, whether the client is in alpha or beta stage.
The software is definitely in beta at the moment. There are many things that need working out before version 1.0 can be declared, like the blockchain for instance - many works in progress. And they're about to completely change the GUI to QT so it certainly wouldn't make sense to declare v1 just before releasing something a lot closer to the actual v1. Patience :)