rickvigorous 80Gb mathematically equates to 2.6Gb a day, or if you're streaming from BBC iPlayer or Netflix around 4 hours a day... I'll be using it to upload photos to my home server and Google photos, do my Blog, Tethered to my Tablet PC and yup while on a long bus journey use it for the kids or myself to watch something or listen to online radio or podcasts.
Ah, the list is endless what you can do with 2.6Gb a day, just don't tether to a laptop or a console or this will quickly eat your data up!
My home fixed Broadband sees close to 1Tb a month as I stream to remote users, and thankfully the devices streaming from the server in the home only use the internal network unless they're streaming from Netflix or BBC iPlayer etc.... It's all a data thing really, this is where it's getting cheaper than voice calls etc....