SQL Diff: 2000 - 2005
Security:Owner = Schema, hard to remove old users at times
Encryption:No options built in, expensive third party options with proprietary skills required to implement properly.
High Availability Clustering or Log Shipping require Enterprise Edition. Expensive hardware.
Scalability:Limited to 2GB, 4CPUs in Standard Edition. Limited 64-bit support.
Security Schema is separate. Better granularity in easily controlling security. Logins can be authenticated by certificates.
Encryption Encryption and key management build in.
High Availability Clustering, Database Mirroring or Log Shipping available in Standard Edition. Database Mirroring can use cheap hardware.
Scalability 4 CPU, no RAM limit in Standard Edition. More 64-bit options offer chances for consolidation.