Like all people I tend to stick to what I know (especially when it comes to tools). I started with SQL Server 6.5 and back in those days isqlw (later Query Analyzer) was really your friend because anything else than creating a table was not really a joyful process. Having this background I am big supporter of Query Analyzer which after all those years I still start using Start - Run - isqlw :-D
When Microsoft announced that the Enterprise Manager and Query Analyzer would be integrated in one big Management Studio I wasn't too happy. Obviously feelings are irrelevant in IT and I felt that I had to face reality one day or another; so I decided to install Management Studio and to start using it from now on.
After some time you will notice that you get used to everything. I have to admit that my unhappy feelings are fading away and I'm beginning to see the 'cool' features of Management Studio. One big improvement is to script all your modifications to an object directly to a Query window instead of the clipboard. Some are simple but very useful like the ability to resize/maximize every window. When it comes to big databases the tree is more intelligent so that it only loads the parts you select. Having to load all tables, stored procedures, ... from all databases while you are perhaps only interested in 1 table in 1 database doesn't make any sense right?
One of the things I immediately changed were the keyboard shortcuts. I'm quite addicted to sp_help and sp_helptext and being able to select an object and get all it's information with a simple shortcut has saved me many hours.