As I mentioned, you really want to make sure that you dont crash your notebook or desktop because you want to satisfy the urge to test IE latest (pre) release.
I remember the old days when Netscape aka Mosaic was around and took 90% in the mid-90’s. Then others came in and they lost valuable time by rewriting the whole thing. By 2006 it fell under 1%. (Read more @ wikipedia). I loved Netscape because it came with a simple editing tool for free, a feature none of todays browser packages offer anymore (per default).
Today we have IE (no. 1), FF (no. 2), Opera, Safari and some other browser.
Since August 2007 Microsoft is working on IE8 and they just release last week the second beta version for public download and evaluation. I propose doing that in a virtual machine. (link)
Microsoft sends 2000 developers in 25 feature teams into the race creating the next release of Windows, Windows 7. They started a blog and reporting on progress and features I guess. They are open to the community to feedback and comment. We should keep an eye on this until 2010 (planned release date).
Check it out @ link
Btw, Microsoft announced there will be no major revamp for a server version of Windows 7.
Check the details @ link