I use SoundCloud, Bandcamp, Google Play and Amazon mostly.
Soundcloud, Bandcamp, iTunes, private tracker for Japanese stuff. I hate using Beatport because it's so expensive but they're the only mass provider of lossless electro and house really. If I can find FLAC or WAVs by other means I will.
I actually get all my music from incompetech.
YouTube
I actually have almost no saved music files on anything I own. If I want to listen to music I just use a playlist on YouTube or play all the songs on a channel I like or whatever. If the internet is really slow or down completely I just turn on the radio.
Bunch of different Vinyl Shops around the city, record on to my computer and play it on my phone, or just listen to it. I really need to get with technology and just buy it online.
I'm using Spotify Premium for that. I get mostly everything i need in nice qualitity.