In the future, definitely. People 10 years ago would have thought a terrabyte as impossibly large.
Now talking from a professional standpoint, I work with GIS (geospatial information systems) and am the database manager at my company, and on occasion, I will have databases that top 1 TB. Its very uncommon and most of the time I find different options (because my IT people bitch that im taking up too much server space) but im talking about it taking county-wide, detailed data and high resolution aerial imagery to make a database that large.
On the other hand, LiDAR data (Light Detecting and Ranging) which consists of billions of data points can eaisly take up a few terrabytes of space...I think I have a 2 TB external hard drive floating around somewhere with filtered LiDAR data for Miami-Dade County.
Those are the heaviest applications I can think of, so you can draw your own conclusions from those examples.