backup - How to choose a storage company?

For an ad agency, I need to find a good storage company.

There are some things to take in considerations :

• Support for different OS (Linux, Mac OS X, Windows Xp/Vista) (if it matters)



• Internal/External systems (through internet or with dedicated servers)


• Redundancy (save on more than one disk and backups)


• Quick transfer


• Automation

Files to be backuped will mainly be PSD, AI files, and documents.

What should i need to know to choose a good provider ?

Any advises (if you know some to compare) (France)

Thanks.

EDIT :

Capicity is about ±2.5Tb

Budget is unknown, and open.