Witch platform shall I use?

Hi there.

For several years, I was sticked to Visual Basic 6.0 (and then, .NET). In the last few years, I have been trying lots of great professional open source software, like CRMs or ERPs. All of them are based, generally, in Java or PHP.

Right now, I work in a company that has an ERP made with Visual Basic .Net/SQL Server 2005 based software. There are specific work that needs to be done that doesn't fit in this software, also doesn't fit in a CRM. Is like something in the middle. I have developed some modules with PHP/MySQL that covers some of this work. My problem is that this modules cannot integrate with ERP applications.

So, my problem is: I want to develop something like a mini CRM, with some specific features, that will mesh up with ERP applications. What do I need:

- I would like desktop applications, because I think that they can be stronger (regarding web browser limitations);
- On the other hand, some of this features, would be available from Internet;
- At any time, we would need new other features, so this platform must be scalable.

I am now stucked on this: witch platform shall I use?

- Visual Basic .NET, because I am familiar with this and is the same platform as the ERP? Well, I wouldn't like to be limited to windows OS;
- Java for the desktop applications? I'm new to Java, but this would be my preferred. I'm just confused with the 1001 programming toolkits and IDEs that can be used.
- Ruby On Rails? I read many good things about it, but its programming language is completely new to me.
- PHP? I am comfortable with it, but I don't know if it suits for this kind of applications?

So I'm stucked. I think I must start with a language, and end with it!

Sorry my lousy english and this long story, but I would like to see others opinions.

Thanks in advance!

Regards,

Paez