Standard or Enterprise SQL Server

Afternoon

I have a question for SQL Geeks

We are looking in to the costs of upgrading from SQL Server 2005 to 2008 and have found that the cost of SQL Server Enterprise is much greater than Standard.  Looking online at the differecences between the two editions I have noticed that enterprise includes the following features;

• Hypervisor support (in Hyper-V)
• Database snapshots
• Indexed views
• Resource governor
• Compression (both data and backup)
• Partitioning
• Transparent Encryption with 3rd party key management
• Transaction auditing (excellent for compliance)
• Change data capture
• Report scale-out
• Grouped server management (one command can be sent to multiple servers)

I'm not sure whether these are important and whether Tessitura needs these features.  What is everyone going for in their upgrades?

Thanks

Nick