In 2006 I won $8500 on a penny machine. Two days later I won $3700 on the same game but different machine. Both at Crystal Casino.
I only play penny machines. Your best bet to win big on slot machines is playing the progressive games. Penny slots can pay out big, as mentioned, and you can last longer then on a .50 or 1.00 machine.
The first big win they took my picture next to the machine for the local paper. The second time when the casino started to take my picture they realized I was already in the camera and decided not to take the picture.
I bet they were happy we left the Island the next day.
A little loss in 2007, about $200 the whole trip.
Oct, 2008 here we come.