We've applied this patch to a lot of systems (3000+) with no ill-effects so far that can be attributed to it.

The odd thing about these worms is that they can flare up again from time-to-time. We got hit by the old Code Red IIS worm two *years* after it was released, on an unpatched server. We have absolutely no idea how such an old worm managed to get onto our network, but it caused a significant amount of disruption.