If there's one thing that people who have read half of the D&D rules get wrong, it's the rules for rolling a natural '1' on a d20. If you are one of those people, allow me to inform you of the correct procedure: YOU DO NOT HIT AN ALLY OR OTHERWISE 'FUMBLE' WHEN ROLLING A 1 TO ATTACK! YOU JUST FAIL! YOU DO NOT SUFFER A COMICAL HUMILIATION WHEN GETTING A 1 ON A SKILL ROLL! IT'S NOT EVEN AN AUTO-FAILURE!" *Ahem*
Botches and fubmles are fun, but only when they provide spice here and there, and aren't happening constantly. So what's good and what's bad?
Abberant/Exalted/Etc: Rolling no successes and any 1's is fairly rare, so humiliating botches don't come up often, so it's usually funny when they do.
Alternity: You critically fail when you roll a natural one on a d20. BUT all the skill descriptions have specific results for what might happen. They're usually bad, but the GM can't just say "gee, a plane falls on you." Plus you have Last Resort Points so you can change it to a regular failure if you really really want to.
Savage Worlds: PCs can 'botch' if they roll double ones; it's not terribly likely, and feels like a holdover from Deadlands. Doesn't impact the game too much either way.
Shadowrun 3rd Edition: Rolling all ones is not very likely to happen. Botches really only occur at the 1-2 level.
Deadlands: Rolling over 1/2 ones happens often enough to provide spice. Botches are only supposed to be so terrible unless you took the Bad Luck hindrance. Huckster backlashes are random botches that regularly happen. They are a feature, not a bug.
New World of Darkness: Penalties have to reduce your roll below zero, and then you have to intentionally choose to roll a chance die anyways. Botching doesn't happen very often, but when it does, you're specifically asking for it.
Shadowrun 4th Edition: You can 'glitch' and succeed on the same action: you get what you wanted, but there's some unfortunate complication. I love it!
d6 Starwars: I've only read through the rules once, but you have a 1 in 6 chance of botching, and the GM is allowed to completely reverse the results of your roll with it. Think about that.
House Ruled D&D: D&D does not have botches or fumbles. Take them out of your game already.
Old World of Darkness: 1s counting as negative successes is really not fun. At high target numbers, botching is exactly as likely as getting a success! Isn't this fun?