I've always liked the idea of getting a max win, (max win screen not necessary), but it's eluded me. In theory what would the easiest slot be? No bonus buys, no wheel gambles, has to be a direct spin.
I'm thinking there must be a slot out there with only one winline, no feature, no repeat spins and a full line of the top symbol still not astronomical that would be a candidate.
Penguin's Christmas Party Time - I've probably just been very lucky but i've spun in 4 max wins on this game in <3000 spins. The max win is low at 2000x though.
edit: misunderstood your question. You mean a game with no bonus and just naturally spinning in a wildline or something that would equate to max? Probably a gamomat game or something they have quite low max win's.
Triple dragons is another one that comes to mind, might be more the kind you're thinking of.