What is the most appropriate document management solution for my requirement ?

Hi All,

I have a requirement for a system or software package which will allow me and other geographically-dispersed users to access Word documents, Excel spreadsheets, database tables, image files, PDFs and emails in an organised and secure manner. Can you suggest the simplest and most appropriate solution given the factors listed below ?

Here's a checklist of my requirements:

1. Users must be able to log on securely to the 'system' and upload and download files/documents/emails via the internet from laptop or desktop.
2. The system administrator must be able to organise files/emails etc in a folder structure and allocate RAID permissions for each user.
3. Inexpensive to purchase and/or maintain.

As we use Microsoft Office 2010 I'd prefer a solution which is compatible with that platform.

I've had a number of suggestions such as Sharepoint, but I don't run Microsoft Server. Google Apps was another option but I couldn't find restrictions for user access.

Thanks
Toco