Here's my favorite... Not the biggest payout (that came from a bartop $1 8/5 BP unit I got four aces on at the Stratosphere).
The one pictured below is for a lot less money, but the results were a lot heavier.
It's an old-school coin-op bartop $0.25 9/6 JoB at Skyline out on Boulder Hwy. It doesn't have a touch screen, but I guess you could call it 'flat' if you count the protective glass over the very-curved CRT underneath it. This was the first 4OAK I have gotten on a coin-op machine, and has therefore earned a place in my book as my 'favorite' win.
Now... here's what it looks like (wish I had zoomed out a bit to show the coin hopper and controls):