2-4 TB/month
Plex streaming from my friends house (untouched Blu-Rays), CrashPlan backups to Friends house and online (In+Out) (new CCTV footage takes the most traffic), and various downloads for work and updates for equipment I test.
I also have another network for my flatmates on a separate VLAN and they use around 400GB/month of the total usage for 5 people hehe...
We are on BigPipe and have never had issues with speed/latency when approaching multi TB/month