DevAge's SourceGrid 2.0 is a great control - full featured, extensible, and some advanced features like virtualization and compact framework support. Unlike many Winform controls, this isn't just a .NET wrapper over a Windows Common Control - it's a new control, written entirely in C#.
Also nice - it's free, and source code is included.
I've been using it for a few months, so I was very happy to see (via the DevAge feed) the DevAge Source Pack Beta 1, including Source Grid 3. Documentation is a little light (although very good for a Beta 1), but the sample code is very helpful. The Source Pack includes some other goodies, like themeing support and typed textboxes. I've used it since it was announced, and it's been working really well. I've been using virtualized grids to enhance performance and minimize memory use. Under Source Grid 2, virtual grids supported a subset of the "real" grid's features' under Source Grid, it's an equal citizen. The new object model uses and adapted MVC pattern - it took a little getting used to, but it's very powerful.
Here's a look at what you can do with it:
The new MVC based pattern: