Advantages of having seperate site collection

The following is a list of what an individual site collection offers.

For the users :

* Dedicated Recyle bins
* Dedicated usage reports
* Distributed administration(site collection administrators)
* Dedicated search scopes, keywords and best-bets
*Custom feature deployments
*Dedicated language translation maintenance
*Dedicated galleries for web parts, master pages, content types, site columns, site templates, and list templates.
*Dedicates shared libraries, such as site collection images and site collection styles
*Dedicated real estate(sefl containment)

For the IT Administrators

*Site quota templates
*Distributed administration
*Site locking
*Database maintenance options
*Bakup/Restore abilities
*Content Deployments
*Infopath forms services global template targeting