I have MediaMonkey installed and use it primarily to edit ID3 Tags, rename files etc. It's a good media player too with support for just about everything, including FLAC, Vorbis, APE etc.
Have no problem with MPC/WMP11+ffdshow+Haali Media Splitter+FLV Splitter. Supports just about everything. Have Quicktime/Real installed too because I sometimes experience compatibility issues (with streaming content) with Quicktime/Real Alternative, although I rarely come across a site that doesn't offer a Windows Media/FLV alternative stream.