I've tried
Media Monkey this should be ok for most people. I didn't like how it changed some file names. It also trashed a couple compilations, by splitting it up into artists.
I've read good things about
Song Bird but never tried it.
Double Twist looked great. But I really don't want to sign up for another service and what the heck was it downloading on the first launch ?
There also is winamp, but that program has gone downhill over the years and I can't suggest it.
I use Foobar to manage my collection from my pc and I but it lacks a sync feature.
Most of these have to many features for me, so I just have a directory and use a batch file to copy my folders over.