To those of you having issues: Have you read the instructions/suggestions others have posted on downloading? I dl'ed on the first day X2 became available to the public - surely the heaviest download period - and experienced no problems whatsoever.
I have a slow to mid- speed DSL connection, and used Firefox with the free DownThemAll add-in to download the whole lot overnight. The next morning, I checked that all the files were there, then I rebooted (for a nice clean system), disconnected internet connection, temporarily disabled antivirus, and ran the executables. All extracted and installed perfectly.
Seriously, the process was about as easy as it could be. If you're having problems and didn't do everything I mentioned above, it's hardly CW's fault.