Another REALbasic alumni, woot!
Having used Objective-C, C#, Python, and a weird JS/ActionScript hybrid, Objective-C remains my all-time favorite language. Unfortunately, it seems as though the reasons I love it (the verbosity, naming all your arguments, square brackets) are also the reasons a lot of other people think it's ugly. And vice-versa(don't care for dot-syntax honestly). I have no opinion on ARC - I'm just happy there's no garbage collection.

I think I'm more of the grouchy old man in the basement with a shotgun and can of beans than the dinosaur though.

As pertains to C# - the Mono runtimes(Mono, MonoTouch, Mono for Mac, Mono for Android) allow you to write some pretty cross-platform C# code — not to mention the cross-platforminess when you use C# with Unity.