Those who want to win the progressive jackpot should play as many lines as they can afford. This will maximize the amount of time you spend on slot machines, and offer you more chances to win the jackpot. Assuming you're just looking to have some fun, it's best to keep the number of paylines under 5.
However, in general, playing at max bet on a cheaper slot machine may give you a chance at winning larger jackpots, while playing at minimum bet on an expensive machine may give you a chance at more frequent, but smaller, wins.