critical updates? should we install?

Microsoft Windows XP

I've read that there are "issues" with the following two critical updates:
821557 and 823980

What is the general consensus regarding the average home user installing
these two updates? I should add that I'm currently using the Google beta
tool bar and I have SP1 on XP Home. Thank you.
The 821557 could *conceivably* be used in conjunction with making a
trojan to install the file on a machine via an internet connection. The
other is one of the ones connected with attacks on a server, and is not
likely - it can be kept out with a firewall anyway. I would not
bother with them myself