I think C# Dot-Net is going to become the defacto platform for most quants and hedgefunds with the exception of those doing high frequency/statistical trading. VB has died and moving to VB dot-net is like moving to Cobol. It's ugly, verbose, and not elegant at all. So MSFT appears to have killed it....on purpose, natch.
I wouldn't get too caught up in what language. Do some C# tutorials, give yourself a simple problem to solve, look at some other programs and understand how they work. The valuable things to learn are how to build common functionalities that solve everyday problems. The language you can use a reference for. After awhile you realize there's nothing myserious about shifting bits around.
Amen. Start with something, anything. Hell, I'd say start with Google Spreadsheets, all the GoogleFinance functions that is. You can trick some things out. Then learn a language with low entry barriers. Preferably one that is used by a friend of yours so he can show you some tips. Perl is good (and more finance calcs are done in Perl than you'd think. It's great at crawling text files with a million lines.) It's free too, and you can use it on windows. Same with Python. You'll see alot of things are very similar - if then statements, while loops, outputs and inputs, objects, etc. The principles are the same anywhere. If you have a knack for it, you'll be able to move to another language easily and quickly (C#, VB, Java, etc etc). The talent of the developer for finding and automating simple but complete solutions to unique problems is much more important than what language they start in.If you demonstrate that knack, then you'll get hired, and they'll give you OJT to learn the language. And you will, quick. If you don't have a knack for it, then look elsewhere. You'll burn out in no time cause for the really talented, developing is a lifestyle. They don't stop when they get home, and consider an all nighter before a deadline fun or a badge of honor or something. It's sick really. Developer's do have great porn collections though. You'll always find the best porn in the IT dept.
None of that is true. The mono project (http://www.mono-project.com) let's you run on Windows, Linux, Solaris and Mac OS X. Also the new C# version has always been 100% backward compatible. You don't have to use the new features if you don't want to. At least it keeps getting improved not like most other old languages. Most developers have abandoned Java that don't have to use it (i.e. because of legacy code or company policy), because there is no advantage of using it over .NET. Check your facts, before you post something that is not true.
Mono is very cool, but doesn't ever seem fully compatible (and a full implementation) of Microsoft's latest releases. I hope it keeps getting better, but it may never get there completely, as is the case with Wine. If it works for what you're doing, great. The fact remains that Microsoft has a long track record of changing its development platforms in a non-backwards-compatible way (although they retain a remarkable level of EXECUTABLE backwards compatibility). And your assertion about "most developers" abandoning Java for .Net seems like FUD to me...
They used to be one version behind, but that's expected since they have to copy what Microsoft comes up with). Thus they can't have the same release circle as Microsoft. If you look at the current roadmap they'll even support C# 3.0 and LINQ in the end of September. I don't know what track record your talking about. For example, the current version of Visual Studio let's you choose which version you want to compile against and you will be warned at compilation if you're using code that will not be compatible in the version you're targeting. And what I said about Java is not my assertion, it's what I've heard from other developers. The fact is, a few years ago Java was the most used programming environment, now it's .NET., so logically they must have moved over to .NET for that to be true.