Recs.
Updated
MusicBee is a media player/library manager for Windows, written in Visual Basic .NET and freely distributed by the author. It organizes collections of all sizes, is highly customizable with third-party plugins and skins, and intelligently scrapes data from several trusted sources to update any empty tags or artwork in files you play.
SpecsUpdate
Pros
Pro Customizable look and feel
MusicBee can be skinned which can significantly change the appearance of a player.
To apply a skin, it must first be downloaded, moved to the appropriate folder, and after restarting MusicBee, it can be applied. A collection of skins can be found here. It's also possible to customize the layout by choosing which panels to display.
Pro Remarkably responsive interface with small to medium numbers of files
Your media library is stored in a flat file rather than a traditional database, limiting its ability to manage truly massive collections of audio files, but offering far reduced processing overhead for small to medium-large collections.
Pro Vast library capabilities - handles a massive collection of music with ease
Current file count exceeds 500,000+. Updates the library faster than other similar feature rich players whilst being fully capable of playback, id tag editing, even visualiser generation simultaneously, limited only by the power of your PC. If your experience is different you likely don't have a capable machine.
Pro Runs well under WINE in Linux environments
There are detailed instructions in the community forum describing how to create a suitable WINE prefix in which to install MusicBee with nearly all the features operating as they do in Windows. There is also support for Linux using CrossOver by CodeWeavers, who offer an automated installer to accomplish the same result on nearly all major Linux distributions as well as Google's ChromeOS.
Cons
Con No shuffle play
Does have an option for shuffle play but this randomizes the songs, which means repeats.
Con Does not handle large numbers of files very well
When opening a large number of files, the interface slows down, album view blocks, process blocks disk every now and then on updates.
Con Doesn't integrate with system media playback interface
Yes it does - Read the manual, check or ask for help at the forum to find out how to use Musicbee.
Con MP3 and AAC transcoding requires installing separate encoders
Due to licensing reasons, MP3 and AAC encoders don't come bundled with the software and have to be installed separately.