I'm looking for games that allow you to build extensively with other people online. Similar to Evony & Habbo. I'm not entirely bothered about the type of game whether it be fighting or socializing. I'm merely interested in the prospect of building and creating things. I don't mind purchasing the game or playing for free.
Additional Note; I'm considering buying Minecraft, is it worth the purchase?
Minecraft is worth it, it is great, you can do pvp, VERY complicated building, simple building, farming, there's also red stone that allows you to make contraptions. Someone even made a red stone computer in minecraft that was more powerfull than the Atari 2600. And you can do all of this with friends. In multiplayer there are MANY MANY mini games that you can try, like survival games (basically the hunger games in minecraft), spleef, races, hide and seek. (Of course, all of the mini games are more than meets the eye) People have also made many "maps" that you can play on, one person made a team fortress 2 map that you can play on with all the classes etc from tf2. If you need more convincing I suggest you watch youtube videos on minecraft, but be careful, ALOT of minecraft videos give very bad impressions of minecraft.
Other than minecraft there actually isn't really any other game like you are describing, all I can think of is roblox Mabey?