EXC_BAD_ACCESS, KERN_INVALID_ADDRESS

Question

For the last two weeks my 12" iBook G4 (800 MHz, 640 MB, OS X 10.3.9) has been crashing in almost every app (Mail, Safari, Microsoft Word, InDesign, iTunes) with the same error in the logs everytime:
Exception: EXCBADACCESS (0x0001)
Codes: KERNINVALIDADDRESS (0x0001) at 0x9622d9a8
I've done the standard things: installed all updates and patches, ran the hardware checks on memory and hard drive, fixed permissions, etc. Everything appears to be fine according to the normal tools but obviously there's something majorly wrong. Short of reinstalling the OS I can't think of anything else to do. I suspect that there's a memory problem or hard drive issue.
Any recommendations for what to try next?
I've convinced two friends to buy Macs in the last 30 days and another 6 to get iPods. I love Apple but this iBook is treating me like a Windows box with they're blue screens of death -- actually my co-workers windows box is far more reliable at the moment!
12" iBook G4 800MHz 640 MB RAM   Mac OS X (10.3.9)  

Answer 1

Yes I use console regularly. There's nothing in the console.log itself, however, the following is shown in every crash log for the different applications:
Exception: EXCBADACCESS (0x0001)
Codes: KERNINVALIDADDRESS (0x0001) at 0x80000000)
My last panic.log reports:
panic(cpu 0): 0x300 - Data access
Everything has to do with data accessing.