Saved my precious several times..
For Programmable AT Fuse
This device is brilliant. I can't stress enough how useful this thingiemabob is. Whether you have a bad PSU, a bad motherboard, a bad add-in card (yes, that Future Domain SCSI controller really did short the bus due to a physical hole in a cap..), or dropping a nut onto a powered build (don't ask me how I know), this thing will save the day.
I suggest you buy one for each of your builds, particularly your test benches or whathaveyou. It looks pricey only until you don't smell the magic smoke when you definitely should have.