C# is also the basic language for Unity is it not?
Java: great - really great - for desktop development, and Android development too. There's precious little money in Android though, and desktop money is extraordinarily hard to come by. Android performance lame.
Well, you've constantly proved that you can write great games using Java :-)
C#: great for XBox tinkering (only tinkering though - XBLIG is basically a cesspit of dross and zero marketing effort, and your chances or making money here are next-to-zero). XNA was good once upon a time but according to various sources is now not-so-good and anyway really only achieves what various other frameworks achieve, no great shakes.
Agree 100% - Microsoft really, really dropped the ball with Xbox Live Indie Games. Use for fun / hobby projects. Still, it's awesome to see your games running on your Xbox. Big smiles there. And you never know, you could get lucky (Fortress Craft or the Dishwasher guy). Only way for most devs to write code for it though unless you miraculously manage to get on XBLA (although would you really want to do XBLA certification *shudder*)
XNA 4.0 is brill - they did a great job of tidying up all the crud. Not sure why people think they broke it - Well, actually I do. Most folks don't realise there are 2 profiles in XNA; Reach and HiDef. And as Reach is the default they assume all the fancy shadery goodness has been nerfed so they could target the Phone. They didn't. They made the reach profile robust enough to hit a wide range of hardware and fix up all various driver problems.
Desktop deployment is sucky though.
Performance often severely lacking compared to Java. C# on Mono stretches deployment to various other targets but again performance is lame.
But Java isn't available on the Xbox so no worthwhile comparison can be made. It's the cheap ass Compact Framework they used that is the reason for 95% of the performance problems. If they have built a framework specifically for the console it would fly. And the in order CPUs don't like the branch heavy code the CF jitter produces.
C++: run anywhere at high speed, with a reasonable amount of hair loss. Rest assured you can do it, but it takes a fair bit longer to get stuff working.
C++11 may take away a lot of the 'pain' of traditional C++ but having not used I couldn't really comment.