uTorrent got iffy once it was bought out. IIRC, you want version 0.6 This was very small, fast and unmolested.
VLC. For years used to be absolutely fantastic. When it came out, a god send. I'd tell anyone listening to use it. Sadly, recently its caused me loads of sync problems, and various other minor niggles. As a result, I have had to reverted to CCCP. When VLC works for me, it is the best, but when it doesn't, CCCP fills the gap. In fairness, maybe a recent VLC update will cure my problems. Dunno.
Foobar2000 needs a mention, especially with Winamp going. My PC is connected to my amp directly via USB, and FLAC files sound incredibly good. (These days, hifi wise, MP3 is, to me, awful. They kinda sound dead. You lose so much detail and depth. But that's a whole new discussion) You can also get a great little app for Android that you can remote control foobar2000 with over your lan.