Since 2008 is coming out without a real rendering engine, I give up. This means that by the time it does come out, it will be old news.
Much more useful will be real time rendering. Assuming that we're staying with Revit on Windows, we're going to need Revit on DirectX 10. If you can't beat the Video game industry, join them. This is the first good thing I've seen about Vista... but only if Revit can get on board soon.
Here is a demo of a new real time engine taking advantage of DirectX 10.
http://www.crysis-online.com/video_downloader.php?dir=/video/SD/(Crysis-Online) GDC 2007 Sandbox Demo.wmv
Now the games look professional and the professional tools look like toys.