I use Spotify to listen to music I already know and like, I use Pandora when I want try to discover new music.

YouTube when I'm on the computer.

I used iTunes for years and years but haven't touched it in ages since converting to my phone.

Pandora pretty much does the same thing. I found most of my current favorite bands off just putting a band I like on there and it playing similar sounding stuff that I've grown to love. Only problem is that all that Pandora does. I used that for years before I even started using Spotify a few months ago, but I do prefer Spotify a lot more and do pay the premium for it, which I don't nor ever will for Pandora. Admittedly I've never tried Spotify's discover features. The main thing that hooked me was being able to play whatever I wanted and being able to keep a playlist of it, which allowed me to eliminate iTunes and synching from my life completely.