Photos half a meg each so 2000 per gig. 100k photos might happen, I have a couple of filing cabinets full of 35mm negatives and contact sheets (ok not family snaps).
Put some music and videos in there and you are away.
Half a meg each? Even my cell phone takes 2-3 MB photos. And then if use iPhoto or something, it stores the original and edited photos separately. My humble personal iPhoto library is 65 GB.
I just looked at my Pictures folder (moving countries later in the year, so seeing if Dropbox monthly might be a short term additional copy solution for those irreplaceable files). Currently at 99.1GB. And there's 83 days of travelling (and photographing) to go before arriving back home.
