I have to agree with the responders, I'd much rather face a commander I haven't seen in a long time than the same "tier 1" commanders you usually see. Myself, I'm a huge fan of Adun Oakenshield.
I'm a big fan of Intervention Pact, but instant-speed buffs to kill with commander damage are big around here. Nothing like making that Hatred with 20 life sac'd to it meaningless. It's saved me from ridiculously large sorcery damage spells like Exsanguinate before as well.
I didn't use it as the only win con, but it was a win con in my Jund indestructible/undying deck when i had that built, along with Obliterate and friends.
I'm glad i don't play against these folks that insist you play the game out when you have a hard lock...
I was in a tournament once and got an infinite turn lock with Thopter Assembly + Time Sieve. One guy had a Glacial Chasm on the board - he asked me to show I had a way to get rid of his land, I searched my library and showed him Ulamog, The Infinite Gyre, he said, okay, good game.
Forcefield is a great card, in my opinion. In most games, it's going to be very useful. Maybe not against every opponent, but there's always someone it will completely deter.
Personally, I occasionally use time magic as a win con in my casual sphinx tribal deck after an overloaded Blustersquall so my army of sphinxes can kill off one player, and another on the following turn, but i have built more competitive decks around Time Sieve in the past.
Identity Crisis. I know it may be a little irrational, but it's a horrible card to get hit with that leaves the rest of the table untouched. I'd rather get Sorin Markov'd.
I've also built a dedicated The Mimeoplasm infect deck that usually killed someone off by turn 3, but infect wasn't quite alternate enough for me, nor as much fun
Although it has only limited usage, I'm a huge fan of Spellskite's redirect ability. While i usually use it to divert spells, people sometimes forget it can redirect targeted activated abilities also. i completely ruined the Kaervek the Merciless player's day when I threw a Darksteel Plate on my Skite.
I think some of you guys are confusing kingmaker with the policy of firing off a last shot in death to take your killer with you. If a guy's killing me off, then sure, I'm going to empty my arsenal to make them pay for it. That's not playing kingmaker, that's fair retaliation.
Kingmaker is when a guy really doesn't have any intention of even trying to win, his only goal is to pretend to be relevant by making someone else win. And that scenario ticks me off to high hell. If you're not playing to win, play a game where they don't keep score.
Avoid Fate says hi, as does Lifeforce.
I was in a tournament once and got an infinite turn lock with Thopter Assembly + Time Sieve. One guy had a Glacial Chasm on the board - he asked me to show I had a way to get rid of his land, I searched my library and showed him Ulamog, The Infinite Gyre, he said, okay, good game.
Personally, I occasionally use time magic as a win con in my casual sphinx tribal deck after an overloaded Blustersquall so my army of sphinxes can kill off one player, and another on the following turn, but i have built more competitive decks around Time Sieve in the past.
I've also built a dedicated The Mimeoplasm infect deck that usually killed someone off by turn 3, but infect wasn't quite alternate enough for me, nor as much fun
Least Favorite Win/Loss: Any game where an opponent (or myself) was mana screwed the entire game.
Kingmaker is when a guy really doesn't have any intention of even trying to win, his only goal is to pretend to be relevant by making someone else win. And that scenario ticks me off to high hell. If you're not playing to win, play a game where they don't keep score.