EZ-Backup

Pr computer:
$5.50/mo
(First 18 GB, compressed)

http://www.it.cornell.edu/services/ezbackup/fees/

Default setting is to backup full computer, including the OS, which makes for a larger backup and thus potentially more expensive.
But the most cost-effective method will requiring carefully and accurately focusing backup on just user's unique docs, not full OS.

File server

Per group:
$9 for 150GB
$30 for 500GB
$60 for 1TB (onwards)

http://www.it.cornell.edu/services/sharedfile/fees.cfm

Set up private folders for each member; can't see each others files.
Has capacity for shared folders, if sharing is desired.
Accessible from off-campus via VPN. CIFS are Windows and Mac-friendly.
NetID-based so usernames and password are easy to remember.

Box.com

Free to CU members, up to 10GB

http://www.it.cornell.edu/services/box/about.cfm

Good for working files. Good for sharing, including to your own, other computers. Limited space.
Individual file size limit is 2GB.
Contact ChemIT if you need more space to discuss options.
Stores Cornell-contracted. Use and rights governed differently than with your group's private DropBox.com accounts, for example.
More space may be available to individuals; contact ChemIT to explore this option.
Service stores prior versions of files, and in most cases also deleted files.
Consider backing up files in case account gets hacked or of a bad internal actor.

• Nightmare story of professor's work compromised while using DropBox.com.
  NetID-based so usernames and password are easy to remember.