Although I'm not a huge fan of Windows, Exchange, and the like, I am a huge supporter (although not current a user - was a SQL Server DBA for a few years) of SQL Server. It is probably Microsoft's finest engineering product. Not only is it a super reliable and scalable system T-SQL is actually a user-friendly SQL dialect, and SQL Server Enterprise Manager (or whatever it's called today) is very user-friendly, too.
Although I'm a true-blue PostgreSQL believer, I give major props to the SQL Server team. In comparison, Oracle is a disaster (I was reluctant/forced Oracle 8i/9i DBA, too).
I actually was a Sybase ASE DBA for quite some time, too (spent a lot of time in the DBA trenches - Sybase ASE is my favorite SQL DBMS) and it's my understanding that SQL Server around the 2000/2005 mark was completely rewritten. Although the origins of T-SQL are Sybase, the rest of the product isn't (some of the philosophy and core architecture still is a carry-over from ASE).
Although I'm a true-blue PostgreSQL believer, I give major props to the SQL Server team. In comparison, Oracle is a disaster (I was reluctant/forced Oracle 8i/9i DBA, too).