I encourage you to check out EMC Corporation's new white paper, "Affordable Data Protection Without The Compromise"

Behind a free registration firewall, the document (linked above) explores the business continuity, size, price and security factors that should be considered when selecting a mid-range data storage platform.

Here's an excerpt, from the Evaluating business requirements" secton of the document:

"It organizations that have experienced the most success with data protection and business continuity initiatives are those that have worked with end users to establish the true business requirements first before making any technology decisions. Business users should be asked two questions regarding specific data and systems- "How much data can we afford to lose if our applications went down?" and "What is the longest outage we could tolerate?" The answers to these questions are referred to respectively as the Reovery Point Objective (RPO) and the Recovery Time Objective (Rto).

"Before jumping into a technology solution, the business user should carefully consider two factors in order to objectively determine the criticality of specific data and applications- the monetary value a specific application and its associated data hold for the business and the costs that would be incurred should this system be unavailable," the document continues. "Once this business value is established, the IT organization and the business unit can make an objective assessment of value versus costs in determining the appropriate level of protection.

"With the emotional element removed, the technology decisions that are made using this approach tend to support the business requirements more cost-effectively."