If all the files you're selling as downloads take up less than 500 MB in total, there's little advantage to using remote file hosting, as you could simply upload the files to us via your product settings without running into your plan's storage limit:
In this case, you would only need to choose a plan level that can accommodate the number of different products (files) you want to sell:
That said, if you'd prefer to use remote hosting anyway, any file hosting service should work if they can provide a static (unchanging) URL directly to the file itself that can be accessed by server-side utilities like wget/curl (rather than requiring access from an actual browser program); you might contact their support team to inquire if they can meet these requirements.
Aside from the services I mentioned earlier in this discussion, we don't really know of other file hosting services that are known to work, because people generally don't contact us to report when things are working fine. Perhaps others can chime in here to recommend what they've used successfully. Amazon S3 is probably the best option that we know of and can recommend, although it can seem a bit techie to set up. You may want to ask a developer to help you set up remote file hosting; we list competent, E-junkie-experienced developers at the "developer directory" link at the very top of this page.