Is the buffering problem on your mobile phone/tablet? If it is android there is a website called App Crawlr that lists a number of apps that will help with the problem. If the problem is with an apple device, I would say that in general, if one of the aps on the website appeals to you, a simple search in the app store will probably find it there too.
Lastly, you could try downloading the songs and movies first and watching them afterwards. It might take a little longer but at least your viewing won't be interrupted by buffering (which I realise is very annoying) and you can delete them afterwards to free up space.
