VLC is meh, it's all about
CCCP +
media player classic (and
CoreAVC if you have an nVidia card and/or a crappy CPU)
Paint.NET A great free image editor...I haven't needed to pirate photoshop since I discovered it.
I'll add a couple of things if you're a music listener:
Foobar2000 Lightweight, great audio quality, infinitely customizable. Absolutely no itunes-type bullshit.
TheGodfather If you have lots of disorganized audio files and want to keep everything uniform this is the easiest way to do it. Batch tagging from file names, or batch file naming from tags. Plus a ton of other stuff.