What should i use to make my minecraft server? Bukkit or spigot?

Bukkit is a lot better to use for compatibility. However if you want to make a 1.8 server then you need an alternative plugin api since bukkit hasn't updated (half the team quit and one filed copyright takedowns on his code when they found out the other half of the team handed over the ownership of bukkit to mojang about two years ago, completely in secret).