Under the "official" rules, 1s are failed saves now. It's no longer just a House Rule. It's in the FAQ, it's in splatbooks, it'll be in the PHB if they ever bother to reprint it.
That being said, I don't like automatic 1s or 20s for most rolls. Sure, random chance should always make ANYTHING possible, but 5% is just way too high for some things.
One of the things we've been toying with: criticals. Here's the idea in progess (haven't tried it out yet):
If you roll a 20 on anything, you roll again to "confirm" the critical. For attacks, criticals deal more damage. For saving throws, criticals might work like Evasion (negate anything that would normally go for half, reduce the duration or effect of a nondamage negative effect by half). For skill checks, a critical is as if you rolled a 30.
If you roll a 1 on anything (attack roll, save, whatever), you roll again to confirm the fumble. For attacks, you hit yourself/break your sword/whatever. For saving throws, you might take double effect (more damage/longer duration/whatever the DM thinks is appropriate) or suffer item damage (as before). For skill checks, it's as if you rolled a -10.
The nice part about this is, it means there's still a slim chance of doing just about anything, but it's now way less than 5% thanks to the second roll.