Just a simple question...

[blackstaff67]

I want to make a sorcerer who grew up as a pool hustler/player.  Should I give him a skill (perhaps a stunt that comes from either Athletics or Performance, mebbe Deceit) to reflect that, or should as Aspect do it?

[bobjob]

Since pool isn't merely a physical endeavor but a combination of physical and mental (doing the math and angles), I would almost consider it a Performance stunt. You are performing a task that requires skill, practice, and coordination. To represent hustling, I would probably restrict it by your Deceit skill since you are trying to get them to up their bets. Looking over the skills there isn't really a clear cut answer for that one.

An aspect that could be invoked would be good too if you wanted to go that route since it kind of defines you.

[Sanctaphrax]

Is your pool skill going to matter in play? Are you going to make money by playing pool, or somehow solve problems by playing pool?

If so, a stunt would be appropriate. If not, there's no point.

Even if you do take a stunt, an Aspect is probably a good idea. It's part of who you are, right?

[Leeder]

I'd suggest you to ask yourself: how do your plan to emphasyse your character's background?

If you don't plan to work as a pool hustler (whatever it is %) ), treat it as an aspect. It is a quality of the character, which can afford help in some situations, though complain other.
If you do plan to work and actively BE a pool hustler in the game, feel free to model it with skills and stunts. You want to show the skills other hustlers have.

Upd. I've read the wiki page on hustlers, and, if you choose the skills/stunts variant, I recommend all of the skills you've mentioned. Deceit, Performance and Intimidation, except you have a stunt, for example, allowing you to roll a trapping of one skill for another.

[UmbraLux]

Is your pool skill going to matter in play?

This.

Go with the aspect.