Amarra by Sonic Studio
Amarra :: High Resolution Music Players and VINYL Restoration
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 (Open Source)
Free
audirvana - OSX Audiophile player - Google Project Hosting
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 very basic at present.
Clementine Player
clementine-player - A cross-platform music player based on Amarok 1.4 - Google Project Hosting
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
Decibel from sbooth.org
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
PixiApps - Ecoute 2 times better, same price !
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
Audiofile Engineering - 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
Play from sbooth.org
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
CHANNEL D - Pure Music
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
Songbird - Welcome
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
Vox :: The Lightweight Music App for Mac OS X
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.