I have a little experience with java (not alot) and none with C#. Although knowing this I would usually head straight to javascript most the tutorials online for unity all deal with C#. When i say I have some java experience it really is not alot at all (extremely basic minecraft modding). So put that into consideration. Should I do javascript or C#?
Javascript or C# in Unity3D?
You should know C# for server side code and Javascript for client side code.
Do C#
knowing javascript would be useful if you ever wanted to make some browser based games, but C# is just a better language for Unity
there are plenty of C# tutorials
http://forum.unity3d.com/threads/unity-c-tutorial-series.185095/
some C# tutorials (not game related)
https://buckysroom.org/videos.php?cat=15
some C# tutorials with Unity
C# Tutorial
http://www.tutorialspoint.com/csharp/index.htm
Visual C# Resources
http://msdn.microsoft.com/...o/hh341490
C# and Java both basically have similar syntax. If you know a little bit of Java then it becomes easier to learn C#.
For Unity, C# is considered as more powerful than JavaScript. You only need to know the core part of C# and the rest of it you have use commands from Unity Scripting Manual for developing your game functionality. Here is a link for it:
http://docs.unity3d.com/ScriptReference/
@James have listed some of the good online resources for learn C#, you can check that out.