I still use WMP 11 for most videos, I use Winamp 5.35 for all audio, .flv videos I use FLVPlayer 1.3.3 and for .gvi videos - Google Video Player.
Since I venture to many websites that have embedded videos I downloaded the Firefox add-on 'VideoDownloader' that allows me to to download embedded videos from a website ie: youporn.com and save to my HDD.