Comparison of SQL Server 2000,2005,2008 features

SQL Server Enterprise Edition	2000	2005	2008
Database Failover	Mainly Replication	Mirroring introduced	Enhanced Database Mirroring
Database Recovery	users to wait until incomplete transactions rolled back	can reconnect to a recovering database after the transaction log has been rolled forward	Enhanced snapshot and mirroring, backup compression which can be further integrated in Log Shipping
Dedicated Administrator Connection		Introduce DAC to access a running server even if the server is not responding or is otherwise unavailable	Enhancements to DAC
Online Operations		Introduce index Operations and Restore possible while database online	Introduce partial database availability
Replication		enhanced replication using a new peer-to-peer model	identity range management,peer to peer and replication monitor improvements
Scalability and performance		table partitioning, snapshot isolation, 64-bit support, Improved replication performance, Introduce covering indexes, Statement-Level Recompiles	Improved core SSIS,SSRS,SSAS processing engines. Performance data collection, Extended profile Events, Backup compression, improved Data compression, single common framework for performance related data collection, Resource Governor
Security		Surface Area Configuration tool, password policies, DDL triggers, catalog views, granular permission sets Encryption	Data Auditing and External Key Management introduced
Availability and Reliability		Memory can be added on the fly and recognized	CPU can be added on the fly and recognized
Application Framework		Service Broker, Notification Services, SQL Server Mobile, and SQL Server Express	Service Broker interface
Developer Productivity		CLR/.NET Framework Integration, Visual Studio Integration, SQL Management Objects, XML Web services, XML Data Type	Date Time Data Type, HierarchyID, LINQ, SQL Server Change Tracking, Table Valued Parameters, Spatial data
Improved BI		A complete BI platform	Enhanced features and performance