Well everybody knows SoundCloud but it has very limited time allowance on free accounts so not so good for sets and mixes really unless you pay for a subscription.
This thread runs through quite a few possibilities:
Personally I use either my own server (not use for ages though) or MediaFire. Although it doesn’t have any streaming I like that it doesn’t have any wait before downloads or limits per hour/day, plus the ability to put files into folders and share whole folder if you wish.
Although maybe Bandcamp would be more to your liking? Not used it myself but always seemed pretty decent…