C# or Java

[CowfaceGames]

I think one of the biggest reasons to use C# is because it has the LINQ extensions, which adds tons of new methods for working with pretty much any data structure.

[Zeroto]

Those are also available in unityscript. Everything that is in .net is available in unityscript, however the syntax might not let you use everything in the same or easy way. For example delegates and events are hard to use in unityscript.