RaceBoarder
Waiting for the Snow to fly...
I don't play slots, but I think I understand what is going on.
Experienced slot players understand that by looking at the progressive numbers that are usually blinking at the tops of the machines, you can see which machine has paid out the jackpots most recently, and which machines currently have higher jackpots. It is also readily known by regular slot players (not me) which machines have more favorable betting odds because of the number of "lines" you can bet.
However, I don't believe you can make a living off of your slot winnings. You might get a jackpot of $30,000, and thus you'll get a Form 1099 from the casino for your winnings (which you'll have to pay taxes on) but slots, even if optimally played, still have a considerable house advantage.
If you read the professional slots threads or sites that are out there, you will see that professional players essentially earn their "living" playing slots by living off of the comps given by the casinos due to their volume of play. Free rooms, food, transportation, etc...
I've also seen it published in different guide books and the like that slots in high traffic areas (near main entrances, washrooms, other attractions, etc.) tend to be fairly loose (albeit via smaller payouts) to constantly show passer-by's that people are "winning" and maybe get them to step in and donate a few bucks when they otherwise wouldn't.