We're about to build a house about 4 rooms, This is such a simple question, which brand of circuit breaker can you recommend and how many amp?. thanks in advance for your replies:)

Most residential breakers are 15 amp and you need to match the wire size with your breaker. Square D and GE are well accepted brand names. You also will need a main panel so be sure the panel accepts the brand of breaker you select, they are not universal. Wire sizes, gauges, for breakers