Harlan Brumm (Autodesk Product Support) posted a great list of known issues / solutions at the Autodesk Forums.

This is a repost of the original, and all credit goes to Harlan Brumm.

Revit Architecture/Platform:

Products Keys for Revit 2011 Products

Clean Uninstall of Revit 2011 Products

Switching to pre-2010, Classic user interface

Resetting the Autodesk Revit Architecture 2011 User Interface

Materials in Revit 2011 FBX are not visible in 2010 applications

Create a custom elevation tag in Revit 2011 products

Rendering with a background image in Revit 2011 products

Revit 20 mile origin limit for imported and model geometry

Cannot tag a room in a linked Revit 2011 project

Rendering processor core limit for Revit 2011 products

Materials in Revit 2011 FBX are not visible in 2010 applications

Rendering with a background image in Revit 2011 products

Materials are not visible in a Revit view set to realistic visual style

Control workset visibility for a Revit link in the host project

Some features may not be fully supported by the video card and driver on this computer

Location for Revit 2011 KeyboardShortcuts.xml file

Revit 2011 additional render paths work differently with realistic views than with rendering

Upgrading IES lights in Revit 2011

In Revit 2011 the PANTONE Find Color field does not search for a matching color

Revit adaptive component does not appear in place a component list

Family containing filled or masking regions appear white in Revit realistic visual style

Revit on Parallels (Mac) with Windows 7 will crash when you click on the Application Menu "R".


Revit Structure:

Object data missing from 2D DWF export

Uninstalling the Autodesk Material Library 2011

Unable to place rebar in column

Using the plan rep subcategory for structural foundations

Error: Slab shape edit failed when setting the curved edge condition


Revit MEP:

Known limitations with panel schedules in Revit MEP 2011

Known limitations with conduit in Revit MEP 2011

Known limitations with cable tray in Revit MEP 2011