Patch 4.3.3 will break the current 64-bit WoW client

This makes me sad as the 64bit client is just awesome. According to blizzard you will need to delete the following files:

In order to patch successfully, you must delete the following files from inside your World of Warcraft folder:

Wow-64.exe (PC)
MovieProxy.exe (PC)
Battle.net-64.dll (PC)
World of Warcraft-64.app (Mac)

We apologize for any inconvenience this issue may cause, but please be aware that since the 64-bit client is still in a testing state that complications such as this may happen from time to time.  Thank you.

http://us.battle.net/support/en/article/64bit-client-prevents-patching-to-433

A updated version of the client will be released soon.