BlogPress does have a file upload limit of 5 GB, but if you hit that limit then we need to have a conversation about alternatives. You really don't want to bog down your site with that volume of file uploads. There are far better options.
Seriously, none of our blogs have ever even come close to that - even our video show blogs!
Tips for keeping your site lean and mean :)
1. Don't upload videos. Instead, upload your videos to a service like YouTube (free) or Wistia (Paid and worth every penny). Then you can place a simple embed code on your site to play the video.
2. Resize images for the internet. There is no reason to display a 1 MB image on your blog. Resize the image so that it's under 200 KB.
3. Use a service like DropBox or Scribd to serve up PDFs, spreadsheets, or presentations.