http://www.head-fi.org/t/539740/mac-os-x-music-players-alternatives-to-itunes
Here's a list from the above link:
Amarra by Sonic Studio
http://www.sonicstudio.com/amarra/
Commercial, demo available for download.
Comes in three flavours: Amarra, Amarra Mini and Amarra Junior with varying features and prices. The player integrates with iTunes, or can be used stand-alone importing tracks into a playlist with one click from the Finder or iTunes. For people with a lot of RAM in their computer, it can be used in cache mode where the files are loaded into memory before playback. Includes iZotope resampling software. However, the licence either requires an iLok USB key or the software is locked to a single computer which can't be transferred.
audirvana
http://code.google.com/p/audirvana/
Free, Open Source
The first player to offer a window that looks like a piece of hi-fi gear, it offers device "hog mode" and up-sampling by default. The feature list is otherwise fairly basic at present.
BitPerfect
http://itunes.apple.com/us/app/bitperfect/id455545700?ls=1&mt=12
Commercial
Integrating with iTunes, this software sits in your menu bar and feeds music via Integer Mode to your DAC. Great if you want a simple and cheap solution while still using iTunes.
Clementine Player
http://code.google.com/p/clementine-player/
Free (Open Source based on Amarok 1.4)
This multi-platform player is more of a music organiser than anything, with features geared in that direction (such as having LastFM support), rather than having any audiophile settings. Thankfully, unlike other multi-platform applications, it isn't Java based (using Qt instead), so the user interface is fast.
Decibel by Steven F Booth
http://sbooth.org/Decibel/
Commercial.
The developer of Play produced a basic, high-quality music player known as AyreWave in conjunction with Ayre. This has now dropped any association with them and has been renamed Decibel. The software itself, while basic, allows one-click importing from files selected in the Finder or iTunes, "hog mode".
Ecoute by PixiApps
http://www.pixiapps.com/ecoute/
Comercial
With iTunes integration, including song rating and metadata support, this is the player for people who want a slick, theme-able one-window interface and want to share your listening habits on Twitter, Facebook or LastFM. It also supports the Apple remote control.
Fidelia by Audiophile Engineering
http://audiofile-engineering.com/fidelia/
Commercial.
With a main window that looks like a piece of high-end hi-fi gear, but far more classy than that of audirvana, it has the ability to play music directly from iTunes playlists without needing to have iTunes running. Also included are a selection of on-the-fly resampling methods, including iZotope and remote control software for the iPhone and iPod Touch available in the App Store.
Play by Steven F Booth
http://sbooth.org/Play
Free.
Until recently, almost the only alternative to iTunes if you wanted a simple music player and nothing else. Allows access to the built-in Mac OS X audio effects filters, which can be very handy if you want a 31-band equaliser, high-pass filter or the like. Since all this is incorporated into Decibel it is probably more worth it to download that instead.
Pure Music by Channel D
http://www.channld.com/puremusic/index.html
Commercial, demo available for download.
Based upon Pure Vinyl and using its own playback engine, like Amarra, integrates with iTunes, running in a window alongside and can re-sample music on the fly. Unlike Amarra, it requires iTunes to be running to select tracks, but offers a considerable slew of other options.
Songbird
http://www.getsongbird.com/
Free.
More a multi-platform internet connected media library project by previous Firefox, Netscape and Winamp developers, it might be easier to consider Songbird to music what Thunderbird is to email, yet a lot more, with online integration.
Vox by Alessio Nonni
http://www.voxapp.didgeroo.com
Free (donations requested).
Much the same as Play, a slowly developed app that does little more than just play music with a minimal footprint. Like Play, it gives access to in-built Mac OS X audio effects filters.