One thing I have noticed about Vista x64 is that the default Windows Media Player is the 32 bit version. Microsoft did this for compatibility reasons with codecs and such. But some people may want to restore the 64 bit WMP in light of a x64 FFDShow being out which decodes virtually all audio/video. Thankfully there is a relatively easy way to switch the system default WMP to x64 and back to x86.
To switch to x64, open a command prompt as administrator and type:
Alternatively to swap back to 32 bit go to a command prompt and type:
So there you have it, a relatively easy way to swap back and forth between x86 and x64 versions of Windows Media Player in Vista x64.
NOTE: It seems that this changes the OS shortcuts but it's not changing the actual file associations, I'm looking into this now.
UPDATE: There is one more step required to complete the transition to a full x64 Media Player.
Go into the registy and navigate to:
And set the Values as follows:
(Default) - "%ProgramFiles%\Windows Media Player\wmplayer.exe"
Path - %ProgramFiles%\Windows Media Player
Include the quotes on the value for (Default).
That's it, now you have a completely x64 Media Player experience. Enjoy!