In Visual Studio 2005 and prior you could export your code to Visio and view the relationships between the objects and what methods, properties and fields it had. This was great as it allowed you to tweak the appearance to improve the look.
In VS 2008 that option is gone, replaced (supposedly) with the class diagram system. It is functional but not pretty.
What I am looking for is some software that allows me to visualise in a prettier way or at least provide me with enough options to filter, arrange and so on so that I could touch it up in something else.
There is a decent, free version of a UML diagramming tool called Argos here http://argouml.tigris.org/features.html. Out of the box it can both forward and reverse engineer Java, I'm fairly certain there are add-ins for Visual Studio that help support forward and reverse engineering of C# code. I would look into that.
Do you require the software to be free? If not, you might consider a UML tool like Sparx Enterprise Architect. It can import your code, and has two add-ons that go further in terms of Visual Studio integration.
Not quite what you're asking for but it's worth checking out some of the add-ins for .Net Reflector
E.g.
Have you tried the PowerToys?