I use a large 60 qt cooler with the milk jug trick, so it doesn't take up alot of space.
Some friends have a 12 volt cooler that they have had for about 10 years, and it works awesome, like said it will freeze things up overnight! I think the way to go is the $500+ models, with dual batteries. You take care of them and they will last forever. Or if you can't justify the price get a couple buddies to pitch in!