I would not go with any smaller than a 4.4cf. As close to 5 as you can get, the better. One of the main things to keep in mind when looking for a mini fridge is to get one WITHOUT a freezer in it. Danby makes an excellent model for kegerators, especially if looking to install a tower on the top of it. Costco runs them on sale from time to time for like $120 but can usually be had for about $150. Hope that helps, cheers!