FATE would be the first game in my 2012 gaming odyssey. I'd read a lot about the system on the RPG.net Forums, and thought that Aspects sounded pretty interesting. An Aspect is a brief statement or description that shows who a character is, rather than what they can do (which is covered by Skills and Stunts). Aspects can provide bonuses in relevant situations at the cost of a FATE point, but they can also be used to earn FATE points when they lead to complications in the character's life. For example, a warrior might have the Aspect "as strong as an ox." This can be used to the character's advantage ("invoked") when a feat of strength is required, but it can also lead to complications. For example, while chasing someone who squeezes through a narrow space, the "strong as an ox" Aspect can be "compelled" to make it harder for the character to squeeze through because of their massive physique.
Aspects can also be invoked or compelled "for effect", which means they do something to the story apart from providing a straight bonus or penalty to a die roll. For example, "Respected NYPD Detective" could be invoked for effect to say that a beat cop who responds to a disturbance is one the character already knows. Likewise, the same Aspect could be compelled to restrict the character's choices and make their life more complicated; a detective may have to follow procedure instead of doing something more convenient but unlawful.
I found the concept of Aspects intriguing because they allow players to gain mechanical benefits from motivations and goals, personality traits, and other intangibles that most games don't track. In many games, when you come to a point where you need to make a roll and something of vital importance is on the line - "if I don't make this roll, my sister will fall to her death!" - all you can do is appeal to the Dice Gods and hope for a good roll. With FATE, you can not only track what's important to your character, but gain a mechanical advantage when it comes into play.
In addition, FATE distributes some narrative control to the players; although the GM has to give their approval, they aren't the only one who can introduce details and elements into the story. Players can spend a FATE point to make a minor narrative declaration - in effect, supply a convenient detail. Players can also use their characters' skills to make declarations - they make a statement, and then roll on a relevant skill to see if it is true or not! The difficulty of this is based not on realism, but on how interesting and useful it would be if the statement were true (or not). The aforementioned "invoke for effect" can also introduce new elements into the story, or colour those already present. In this way, FATE is a game where the group truly collaborates to create a shared story.
Aspects, Skills, and Stunts are the three basic pillars on which FATE characters are built. Skills work pretty much as they do in any other game, although their performance can be affected greatly with Aspects. Stunts are ways in which the character can break the rules; granting permanent skill boosts or allowing one skill to be substituted for another in a specialised area, providing companions or sidekicks, or other more esoteric modifications.
FATE's Different Aspects
There are many different versions of the FATE system, each of which has its own approach to Aspects, Skills, Stunts, and various subsystems specific to each game.
I picked up Spirit of the Century (and Trail of Cthulhu) on a visit to an out-of-state game store over the 2011 Christmas/New Year break. When I got home I did a little research into the evolution of FATE, and discovered that SotC was the first iteration of FATE 3.0. Most of it was a pretty interesting read, and it took the time to explain itself in detail. However, this verbosity also reduces its usefulness as a reference book, as you need to hunt through more pages to find a specific ruling. Also, I'm not a huge fan of the pulp genre, and I was a bit turned off by some of the setting elements. Probably my least favourite part of the book, though, was the Stunts section - so many of them, each with its own effect and prerequisites. Things like this tend to turn me off, because it requires the players to read and digest a sizable chunk of rules just so they can make properly informed choices about their character. When it's voluntary, like choosing to make a wizard and having to read through a list of spells, that's a different matter.
I ended up buying Strands of FATE because of its wildly different approach (although as of Jan 2013 I've yet to do more than read through some of it). I also picked up a copy of Free FATE, a 48 page stripped down presentation of FATE 3.0. I decided to use this slim version to run my first FATE game; partly because it explained things clearly and succinctly, but also because it had broken down that massive Stunt chapter into just a few pages, and included basic templates so you could easily build your own.