SQL Server 2000 has always been one of my favourite bits of software. I have written various software that runs on top of MSDE and always been really pleased with it.
Having spent a great deal of time recently working with Oracle 10, I have really noticed how much easier administration is with SQL Server. I have also had lots of issues with Oracle drivers (in particular where CLOB fields are used).
I have to admit to being rather underwelmed by SQL Server 2005. I'm not a great fan of stored procedures (I believe the logic should be in a middle tier) and certainly not of running .net code inside a DB server.
One thing I was looking forward to was the addition of spatial algorithms to SQL Server.
Wikipedia notes that spatial data is planned for the next version, but for the mean time I will be using Oracle for my clients, and personally Postgres.
I think Microsoft really missed out here. More and more of my clients need to store spatial data, I would love to use SQL Server, but my money has to goes to Oracle or an open source database.
Pull your finger out Microsoft and make sure 2008 is spatial enabled !