In this hobby? Yeah you can never get too much hard drive space. Amazon has several 2TB drives under $120.
I have several (both internal and external) of 1TB or more. I like keeping backups and I don't feel like pushing it all up to "the cloud".

I probably go a bit overboard really but if you have like a full mame rom and CHD set and a bunch of other consoles plus artwork and preview movies for your frontend and maybe a nice big mp3 collection and family photos/video... Yeah even that 2TB can fill up quick. Once games started using optical media the rom sets started getting huge if you're into that sorta thing.