FastSpring ( http://www.fastspring.com/ ) looks pretty good. I was wondering if anyone had experience using them or if there other platforms I should investigate.
Probably useful for podcasters and theater shows too. Similar to this: http://www.ambrosiasw.com/utilities/soundboard-mac/
Also plan on selling "packs" of themed music and SFX.
There are a bunch of alternatives
as for eCommerce that might be a little specific so I would do as much research as possible.
Obviously don't use paypal
4 bad reviews from the same person within an hour locked her paypal account and all the money inside for 6+ months. She wasn't allowed to sell more than 10 items a month when she was averaging 100+ items a month. It was feeding her and her kids. Weeks went by and she didn't have any money so she went on food stamps for those 6+ months. Paypal simply didn't give a fuck and after 1 email where she asked very nicely why she couldn't sell more than 10 items they locked her account indefinitely. 2 years later she still doesn't have the money and she isn't allowed to sell under any other ebay usernames.
Well if that didn't happen she wouldn't have found her new job making triple the money at an actual store front.
Besides that story I would recommend using something like braintree in order to make them stronger and grow.
Paypal can suck my dick :)
Unfortunately https://www.braintreepayments.com/ is not world wide yet (I'm in New Zealand) but I will keep an eye on them.