What are the key differences between Microsoft's SQL Server 2005 and SQL Server 2008?
Are there any compelling reasons for upgrading (any edition, as I have a customer with multiple editions)? Or is there a website with either a chart or bullet point comparison of the two servers?
Also, is there anything noteworthy in the Express editions of either version?
(Good intro article part 1, part 2, part 3. As for compelling reasons, that depends on what you are using SQL server for. Do you need hierarchical data types? Do you currently store files in the database and want to switch over to SQL Server's new filestream feature? Could you use more disk space by turning on data compression?
And let's not forget the ability to MERGE data.