When it comes to shoes there are no particular models designed specifically for longboarding, so you have a very wide selection here. The longboarding shoe should be comfortable and durable. Here are a few suggestions based on our experience.
Vans Old Skool Pro (~$75) Not very cheap but very comfortable shoe with extra cushioning and durable sole which is important if you foot-brake a lot. The iconic Vans look is a nice addition as well.
Nike SB Check Solarsoft (~$60) These are also incredibly comfortable, designed with skateboarders in mind. The sole can take lots of foot-braking.