@MAS3,
I've been using 1N4001 - 1N4007 as flyback diodes for relays and solenoids for years because they seem to be the ones I see most in schematics I find online. When you guys started talking about how it MUST be a FAST diode I just figured "if you can't beat, join em'" so I linked this Schottky diode:
This is the first time I have seen anyone say a 1N4001 was not adequate for a flyback diode. I don't know if that's true yet.