We have a web application dedicated for serving up files and this is what I can tell you from my experience. The design of the web app is to house executables, license codes, and installation guides, so pretty similar to your requirements. The executables can range from 4MB to 1.5 GB with guides in the 200k range.
Under normal load, there aren't too many problems. Wait time for fetching the larger files out of the database can take upto 3 minutes for local users. Recently, we've been moving files out of SharePoint and putting them on a web server restricted by AD permissions and use the Link To Document content types to maask the file location.
This allows us to use the interface and security of SharePoint to give users access to the appropriate files and gives the users instant access to the file instead of waiting for it to be sucked out of the database and presented to the user.
This is definately not what Microsoft intended for the use of SharePoint. It has worked well to distribute some of the smaller executables and you might be safe if the max size you're anticipating is 500 MB. How it will scale out to a global deployment, I cannot tell you.
I should also note that we tested BLOB offloading of these files with no noticible impact on the speed of delivery.