The answer is: it depends. In fact, Unified Communications means totally different things to different people.
By merging voice and data networks, unified communications solutions help businesses make real time delivery of information a simple task; but what works for one business might not be functional to the next. Therefore, identifying what type of information really needs to be delivered and how is the key to a successful Unified Communications deployment.
The bare minimum features in a unified communications setup to help enhance user productivity and business processes are: voice, presence, unified messaging (receiving voice mail and fax through email), CRM integration (i.e. with Salesforce.com) and call conferencing.
Deciding whether features such as chat, videophone or telepresence are important business tools or expensive business distractions really depends a lot on the management’s viewpoint.
In summary, once an organization decides to get rid of a traditional PBX, the next step should be to assess what exactly the business’ communication needs really are before making the next investment. Once these needs are identified, a sensitive solution would be to then go for an IP PBX that is vendor-independent, that is easy to deploy and use, and that comes at a competitive price.