I just bought a "Lifetime" brand hard-side cooler from Walmart. $78. Love the latches and used it on a recent fishing trip - kept the original bag of ice (small one) for 4 days.
It's sturdy (can sit on it, stand on it), doesn't slide around. Has a nice padded handle tot carry it too.
It's heavy when full - but all of the "super coolers" are. It's perfect for the boat as long as you're not lugging it long distance.