I've been using GSPlayer about a month and like it (despite some quirks). Chose it because it is free and has an AAC (m4a) plugin (I have a lot of AAC format music in iTunes I don't want to convert to mp3). [Don't anyone get your dander up about iTunes; I don't endorse it but it is convenient, that's all]. If you have mostly mp3's, there are several good players as mentioned around the forum.
Using iTunes Agent, Softick Card Export (unfortunately, not free), and iTunes Export, I can sync iTunes to my storage card and convert iTunes playlists to m3u playlist that GSPlayer reads. Can provide more details on how that works if someone wants.