I opt to NEVER INSTALL AN EXTERNAL CODEC PACK!
No need. WMP and WMC standard Win7 media foundation support can play just about anything (but admittedly, not everything).
If I want some type of special video format to play that for some rare reason is not supported by either WMP or WMC, I use
PotPlayer which for my money (actually, it costs NO MONEY... it's free!) is superior to every other media player out there including VLC (VideoLan). Haven't run across any audio or video format not playable with PotPlayer directly.
Note that PotPlayer includes support for FLV, MP4, all audio and video formats, etc., and you can optionally set PotPlayer to be the default Windows player for any of these. I'll actually use Winamp for my default audio player, and PotPlayer manually invoked when I want to play "uncommon video"
You don't need any external codec packs... just PotPlayer. Same as with Winamp for audio, which can play all audio formats by itself with no external codecs installed.
The PotPlayer program has a vast amount of customization capabilities allowing you to control its GUI appearance and behavior, but once you get what you want you can save your customizations to an INI file which can then be used to automatically carry forward these customizations any time you might upgrade the program to a new release.