VLC essentially has the codecs (mostly libavcodec) built in rather than using the DirectShow "modular" design, which is a design decision made due to its cross platform nature (can't use DirectShow on OSX or Linux now can we). This is good and bad. Good because it's simple. Bad because it doesn't give you any choice for playback, and it doesn't allow for easy expansion. It generally handles what it handles and nothing else. I like VLC for some things, but it's color fidelity and playback quality aren't really up to par on some media types -- especially newer MPEG-4 AVC codecs.
The codecs it uses are from the FFMPEG project, which is effectively the same set included with FFDSHOW and Media Player Classic. Installing a good, solid filter set including FFDSHOW (such as CCCP) will give you the same playback capabilities as VLC in any DirectShow player.