A-2-3-4-5 is considered a five-high straight, and it is called a wheel or bicycle; this is the only time an ace plays as a low card. An ace-high straight flush is called a royal flush and it cannot be beaten. The only time it ties is when all 5 cards to the royal flush, i.e. A&e K&e Q&e J&e 10&e, are on the community board.

Basically, the rule states that you must make ten times the raise size from the total pot when set mining, twenty-times the raise size when calling with suited connectors, and thirty times the raise size from gapped suited-connectors.

Stud Hi-lo or stud 8 come to mind as the most skill weighted because paying attention to the dead cards and actually remembering them all will give a massive advantage over someone with a weak memory. I think draw games require the least skill but I could be wrong.