on the speed of your internet connection. That is the overriding consideration and the driving force.
Anything else is secondary and if your system is free of malware and otherwise performs well, no amount of helper software will make any difference.
I assume you mean 'streaming' of movies and videos as in YouTube and such. Actually downloading of movies is a different situation and one fraught with difficult questions like copyright ownership and piracy.
I think it is a problem nowadays - wait lots of time until movie downloads enough to start watching it. I believe that in future all content will be located in web but what about speed ? If I calculate all time I waited for video to be downloaded it could be days... do you know any tool which would help my browser to download video in several threads at least ? I didn't find such... I found only JCopia which allows only to download it on disk. Any suggestions ?