Sometimes you want to edit data directly in a table (often a very bad idea!). In Enterprise Manager (SQL2K) and SQL Server Management Studio (SQL2K5) you right-click a table and select "Open Table" from the menu. That brings back ALL of the rows in the table, and you edit them that way. This has a bad habit of locking tables while all that happens.
So in SSMS 2K8, we added two menu items - "Edit Top 200 Rows" and "Select Top 1000 Rows". Now you can edit just a few at a time or view them. By the way, these numbers are a value you can set in the Tools | Options menu.