What is the best music player for Linux ?

Clementine music player is an iTunes like music player and has multiple OS versions http://www.clementine-player.org/downloads

Though, if you just want a player, VLC is the best

What would be distinguishable about "the best music player for Linux"?

Perhaps you'd consider "the best music player for Linux" to be the one that uses the least resources, or maybe you're not so worried about resources, but you'd like to play lots of different media formats? Perhaps you're not fussed with either of these and you just want something you can put skins on or make transparent or integrate with your desktop?

We can't read your mind. Tell us exactly what you want and we might be able to give you a better recommendation.

I have never used iTunes, so I'm not sure what's similar. I've always liked Amarok though. It's the default audio player in many KDE distros. Some features it has is an integrated equalizer using Phonon, dynamically displays song lyrics and pulls up the Wikipedia page for the band (if there is one).

Banshee is the closest media player to itunes for linux, it should have no issues syncing music to ipods or iphones (however app will not sync)

If you like iTunes try Amarok or you can buy songs from Ubuntu One.

iTunes in WINE...........

With the help of a few addons and themes, Songbird can become very similar to iTunes. For example, you can easily find iTunes-like themes and there are addons for features like Cover Flow. By default, the layout itself is very similar to that of iTunes (buttons at the top, songs below) so you won't need to worry about learning anything new.

Banshee is about the closest you will get to iTunes, it offers very similar functions, there's a music store, you can sync, most, iPods using it.

If you really wanted to use iTunes you could run it through Wine although this may require a lot of extra work and if you're new to Ubuntu I wouldn't advise it. Still, if you really want to run iTunes, here's the Wine link for it WineHQ - iTunes.

I would try out Google Music Beta (music.google.com). You have to sign up and wait for an invitation, but it lets you sync your music from Windows and play it on Linux. Another one of my favorites is VLC.

I prefer Rythmbox Player... Simple and easy to use...