" EXT3-fs error (device ide0(3,1...: 2Time(s)"
In the past I had a lot of problems with a Maxtor secondary IDE controller using a Promise chipset. The I/O errors were sometimes reported as disk errors and sometimes reported against the IDE port. Since you are having errors on IDE0 I would cast a suspicious eye at the IDE chipset.
Does your new motherboard have a different IDE chipset than the old? Does your kernel have support for the new IDE chipset or is it still configured for the old IDE chipset?
"In 10 years dealing with linux/solaris I have never seen a version of fsck fail to fix a file system without a hardware problem, much less cause a kernel panic!! Maybe I was just lucky?"
I have seen it happen on my Maxtor secondary IDE controller (which is now residing a long throw away in my backyard).
There is a problem found on several IDE chipsets that you might investigate. The chipsets are supposed to have two independent data paths, one through IDE0 and one through IDE1. Several IDE chipsets have a hardware bug where they can only use one path at a time. An attempt at simultaneous access through IDE0 and IDE1 results in a hardware error. The manufacturers fix this problem by writing Windows drivers that never allow simultaneous access. Then the manufacturer keeps mum about the fact that the top transfer speed on their chipset is only half of what it should be. They also refuse to release this information to the public so the Linux driver developer has to reverse engineer how the device work, errors and all. So even if you have the correct Linux driver then it still may be flaky because the driver does not play the bugs correctly.
If you suspect that you have a driver/chipset problem then the best place to look for the problem is on the development board used by the people who developed that driver. Also you can go to www.kernel.org
and scan every changelog for kernel versions newer than yours for your chipset name. See if you can find where a developer makes kernel IDE driver changes to get around hardware and/or driver bugs.
Be prepared. Create a LifeBoat CD.