The best is hard to quantify and it depends on your needs. SQL Server Reporting Services client reports are built into VS and SQL Server Express supports server reports too. It used to at least, but I haven't checked for a while. That's all free and can do what most lone developers need so I'd generally say why look any further?
As aside. C# is a programming language, but the .NET Framework (and it's various implementations) is a platform. Yes, C# maybe the most common language used on the platform, but there there is also VB.NET, F#, IronPython, etc.