to start, i use nova launcher, and i actually bought prime a couple weeks ago. amazing launcher if you've never tried it before.
for a music player, i use Omich Player (can be downloaded here: https://play.google.com/store/apps/d...ichsoft.player)
this is a really fast, simple music player that kinda looks like the really old versions of Google Play Music, but without any of the cloud crap :P and it's free. unfortunately it doesn't have gapless playback for me (but anything using the android music API on ICS doesn't have gapless) and i'm not a huge fan of pirating apps on android (malware gets spread pretty easily through cracked APKs)
next up, for a file manager, i use the OI File Manager (can be downloaded here: https://play.google.com/store/apps/d...ts.filemanager)
ever since i had cm7 i really liked this file manager, even though it doesn't have root permissions, but it's simply one of the best solutions out there. nice, clean interface, easy to use, open source, and it just works really well. the latest version has some UI glitches every now and then, but i hardly use it anyway so it's fine. file managers are just nice to have around, especially this one.
oh and there's also the obvious titanium backup with pro version (you need the pro version, it's seriously gimped without it)