I just updated a different system with aptitude that was using the main Ubuntu repo (us.archive.ubuntu.com) and got the same results:

Original versions:
cat /proc/version
Linux version 2.6.24-21-generic (buildd@palmer) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Mon Aug 25 17:32:09 UTC 2008

gcc --version
gcc (GCC) 4.2.3 (Ubuntu 4.2.3-2ubuntu7)

After update:
cat /proc/version
Linux version 2.6.24-21-generic (buildd@palmer) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Tue Oct 21 23:43:45 UTC 2008

gcc --version
gcc (GCC) 4.2.4 (Ubuntu 4.2.4-1ubuntu3)

cat /var/log/aptitude # Pardon the cat abuse
Aptitude 0.4.9: log report
Sun, Nov  2 2008 12:30:13 -0500

IMPORTANT: this log only lists intended actions; actions which fail due to
dpkg problems may not be completed.

Will install 38 packages, and remove 0 packages.
717kB of disk space will be used
===============================================================================
[INSTALL, DEPENDENCIES] libisc35
[UPGRADE] acroread 8.1.2.su1-0.0medibuntu0.8.04.1 -> 8.1.2.su1-0.0medibuntu0.8.04.2
[UPGRADE] acroread-escript 8.1.2.su1-0.0medibuntu0.8.04.1 -> 8.1.2.su1-0.0medibuntu0.8.04.2
[UPGRADE] acroread-plugins 8.1.2.su1-0.0medibuntu0.8.04.1 -> 8.1.2.su1-0.0medibuntu0.8.04.2
[UPGRADE] apt 0.7.9ubuntu17 -> 0.7.9ubuntu17.1
[UPGRADE] apt-utils 0.7.9ubuntu17 -> 0.7.9ubuntu17.1
[UPGRADE] bind9-host 1:9.4.2-10ubuntu0.1 -> 1:9.4.2.dfsg.P2-2
[UPGRADE] cpp-4.2 4.2.3-2ubuntu7 -> 4.2.4-1ubuntu3
[UPGRADE] dnsutils 1:9.4.2-10ubuntu0.1 -> 1:9.4.2.dfsg.P2-2
[UPGRADE] g++-4.2 4.2.3-2ubuntu7 -> 4.2.4-1ubuntu3
[UPGRADE] gcc-4.2 4.2.3-2ubuntu7 -> 4.2.4-1ubuntu3
[UPGRADE] gcc-4.2-base 4.2.3-2ubuntu7 -> 4.2.4-1ubuntu3
[UPGRADE] gstreamer0.10-plugins-bad 0.10.6-5 -> 0.10.6-5ubuntu0.1
[UPGRADE] gtk2-engines-pixbuf 2.12.9-3ubuntu4 -> 2.12.9-3ubuntu5
[UPGRADE] libbind9-30 1:9.4.2-10ubuntu0.1 -> 1:9.4.2.dfsg.P2-2
[UPGRADE] libdns35 1:9.4.2-10ubuntu0.1 -> 1:9.4.2.dfsg.P2-2
[UPGRADE] libffi4 4.2.3-2ubuntu7 -> 4.2.4-1ubuntu3
[UPGRADE] libgcc1 1:4.2.3-2ubuntu7 -> 1:4.2.4-1ubuntu3
[UPGRADE] libglib2.0-0 2.16.4-0ubuntu3 -> 2.16.6-0ubuntu1
[UPGRADE] libgomp1 4.2.3-2ubuntu7 -> 4.2.4-1ubuntu3
[UPGRADE] libgtk2.0-0 2.12.9-3ubuntu4 -> 2.12.9-3ubuntu5
[UPGRADE] libgtk2.0-bin 2.12.9-3ubuntu4 -> 2.12.9-3ubuntu5
[UPGRADE] libgtk2.0-common 2.12.9-3ubuntu4 -> 2.12.9-3ubuntu5
[UPGRADE] libisccc30 1:9.4.2-10ubuntu0.1 -> 1:9.4.2.dfsg.P2-2
[UPGRADE] libisccfg30 1:9.4.2-10ubuntu0.1 -> 1:9.4.2.dfsg.P2-2
[UPGRADE] liblwres30 1:9.4.2-10ubuntu0.1 -> 1:9.4.2.dfsg.P2-2
[UPGRADE] libstdc++6 4.2.3-2ubuntu7 -> 4.2.4-1ubuntu3
[UPGRADE] libstdc++6-4.2-dev 4.2.3-2ubuntu7 -> 4.2.4-1ubuntu3
[UPGRADE] linux-headers-2.6.24-21 2.6.24-21.42 -> 2.6.24-21.43
[UPGRADE] linux-headers-2.6.24-21-generic 2.6.24-21.42 -> 2.6.24-21.43
[UPGRADE] linux-image-2.6.24-21-generic 2.6.24-21.42 -> 2.6.24-21.43
[UPGRADE] linux-libc-dev 2.6.24-21.42 -> 2.6.24-21.43
[UPGRADE] pciutils 1:2.2.4-1.1ubuntu5 -> 1:2.2.4-1.1ubuntu6
[UPGRADE] thunderbird-locale-en-gb 1:2.0.0.0+1-0ubuntu1 -> 1:2.0.0.14+1-0ubuntu1~8.04.1
[UPGRADE] tzdata 2008h-0ubuntu0.8.04 -> 2008h-0ubuntu0.8.04.1
[UPGRADE] wine 1.1.6~winehq0~ubuntu~8.04-0ubuntu1 -> 1.1.7~winehq0~ubuntu~8.04-0ubuntu1
[UPGRADE] xkb-data 1.1~cvs.20080104.1-1ubuntu6 -> 1.1~cvs.20080104.1-1ubuntu8
[UPGRADE] xserver-xorg-video-intel 2:2.2.1-1ubuntu13.6 -> 2:2.2.1-1ubuntu13.7
===============================================================================

Log complete.