Software is a complicated beast – even with a lot of testing and additional beta releases bugs will go through.

That is why I NEVER install a "full release" numbers, like Photoshop 6.0 or WordPress 2.9 – I always wait until the x.1 patch is out.

In the case of Windows you should always wait for the first service pack.

Only when the software is out to thousands or even million of users all bugs will rear their ugly heads – so let others do the painful testing of the new release and only install the patched "new" version.