Typical week for www.beebware.com:
Data transferred: 2.566 Gbytes
Average successful requests per day: 21,165
Distinct files requested: 50,764
Distinct hosts served: 14,185
Of course, there is a password-protected 'adult' section (nowt hardcore though), but some hosts won't touch it because of that.
Place I work at though, has 14x2Mbps lines - mainly for 1 server which has 26Gb of incoming traffic per day...