User account won't boot, files to change/check?

Hi all,

I've got a mid-2010 MacBook Pro 15" that I've retired from active duty due to the known video card problem, but I still use it as a remote jukebox. Last week, it started dropping out during iTunes playback, so I rebooted it. Only, it never successfully rebooted into my user profile and still can't.

The machine hits the living screen, and with Find My Mac I had the Guest account that I could boot into. I also ran the standard Rescue startup and ran Disk Utility several times, finding errors but apparently never fixing anything that was the root cause. I also reinstalled the OS, no improvement. From the Guest account I could create a new admin account and think I have full access to the machine now. And most importantly, it boots all the way into that new account. But the same problem with my original user account remains unsolved. Rather than wipe everything down and start over, I'd instead love to try trashing some .plist files or something in order to try and remove the login problem.

Any thoughts on this? Is there a useful canonical list of configuration files that can be moved or trashed through su from my new account to try and restore bootability?