Good idea with this thread, congratulations.
Just to add something useful for the thread, here is my tip: (for n00bs, or a "newbie-n00bs" since I consider myself a n00b too
No matter what, DON'T PANIC.
If your phone boots at least partially (the bootloader starts and shows R/G/D versions) maybe its not that bad
I've flashed few times "bad ROMs" and my phone stucked on bootloader. Luckily none of them was that bad that I couldn't recover from it.
What I do first:
disconnect the phone from anything you had it connected to,
and go into bootloader mode (camera button + reset with stylus).
It will show the tricolor+white screen, SPL version on the top and "Serial" at the bottom.
Plug in your USB cable.
If the "Serial" will change into "USB" at the bottom, you are most likely ready to fix the problem
- so flash your phone with new clean ROM now (I would go with clean stock ROM including radio as well)
oh, and don't worry about the ActiveSync info that may be displayed by the RUU app, because you are already in bootloader mode (RUU or KaiserCustomRUU etc, at first disconnects AS in order to set your phone in bootloader mode, thats why the warnings about AS being "green" etc)