One of the most common reasons cited for not learning more about functional programming is the lack of both good libraries and good development environments. This is a little bit surprising, because when it comes to learning a language, these two features are likely to have the least impact on the learning process. Despite that, this lament continues; there must be more to it!
Programmers, like most folks today, are largely short on time. Wherever they invest it, they expect a good return. When it comes to programming, every programmer hopes that the investment he makes in learning a new language has at least a fighting chance at being applied to solving a billable problem.
F# completely blows away these two huge barriers to folks learning more about functional programming: it has complete access to the .NET platform and has excellent integration with Visual Studio .NET.
This is very, very exciting: even if a programmer never ends up using a functional programming language for billing work, he will have had a lot of fun learning a new paradigm, and will be a better programmer for it!