Does an analysis/optimization tool like SqlYog exist for SQL Server 2005 (and later)?
Microsoft provided, for free, SQL Server Management Studio (SSMS) starting with SQL Server 2005. Is it not exactly like SqlYog but there are similarities. With regards to table space I would direct you to the Standard Reports that were added to SSMS after SQL 2005 SP2. They provided a more eye friendly look at allocation of space, index usage, performance information, etc.